Use `{units}` package in functions that return values with units

[PietrH]

          There are 243 possible entries for `log_data`:

id_pk	metadata_type	col_index	col_name
1	DIAG	0	Device Time (UTC)
2	DIAG	1	Time
3	DIAG	2	Time Offset (h)
4	DIAG	3	Time Correction (s)
5	DIAG	6	Ambient Temperature (deg C)
6	DIAG	7	Noise Mean (mV)
7	DIAG	8	Tilt (deg)
8	DIAG	9	Depth (m)
9	DIAG	10	PPM Pings
10	DIAG	11	PPM Detections
12	ATTITUDE	0	Device Time (UTC)
13	ATTITUDE	1	Time
14	ATTITUDE	2	Time Offset (h)
15	ATTITUDE	3	Time Correction (s)
16	ATTITUDE	4	Model
17	ATTITUDE	5	Serial Number
18	ATTITUDE	6	Tilt (deg)
19	BATTERY	0	Device Time (UTC)
20	BATTERY	1	Time
21	BATTERY	2	Time Offset (h)
22	BATTERY	3	Time Correction (s)
23	BATTERY	4	Model
24	BATTERY	5	Serial Number
25	BATTERY	6	Battery Position
26	BATTERY	7	Battery Type
27	BATTERY	8	Battery Serial Number
28	BATTERY	9	Battery Voltage (V)
29	BATTERY	10	Battery Remaining (%)
30	CFG_CHANNEL	0	Device Time (UTC)
31	CFG_CHANNEL	1	Time
32	CFG_CHANNEL	2	Time Offset (h)
33	CFG_CHANNEL	3	Time Correction (s)
34	CFG_CHANNEL	4	Model
35	CFG_CHANNEL	5	Serial Number
36	CFG_CHANNEL	6	Index
37	CFG_CHANNEL	7	Frequency (kHz)
38	CFG_CHANNEL	8	Decoder
39	CFG_CHANNEL	9	PPM Map ID
40	CFG_CHANNEL	10	HR Coding ID
41	CFG_STATION	0	Device Time (UTC)
42	CFG_STATION	1	Time
43	CFG_STATION	2	Time Offset (h)
44	CFG_STATION	3	Time Correction (s)
45	CFG_STATION	4	Model
46	CFG_STATION	5	Serial Number
47	CFG_STATION	6	Station Name
48	CFG_STATION	7	Latitude (deg)
49	CFG_STATION	8	Longitude (deg)
50	CFG_STUDY	0	Device Time (UTC)
51	CFG_STUDY	1	Time
52	CFG_STUDY	2	Time Offset (h)
53	CFG_STUDY	3	Time Correction (s)
54	CFG_STUDY	4	Model
55	CFG_STUDY	5	Serial Number
56	CFG_STUDY	6	Description
57	CFG_TRANSMITTER	0	Device Time (UTC)
58	CFG_TRANSMITTER	1	Time
59	CFG_TRANSMITTER	2	Time Offset (h)
60	CFG_TRANSMITTER	3	Time Correction (s)
61	CFG_TRANSMITTER	4	Model
62	CFG_TRANSMITTER	5	Serial Number
63	CFG_TRANSMITTER	6	Transmission Type
64	CFG_TRANSMITTER	7	Full ID
65	CFG_TRANSMITTER	8	ID
66	CFG_TRANSMITTER	9	Power Level
67	CFG_TRANSMITTER	10	Min Delay (s)
68	CFG_TRANSMITTER	11	Max Delay (s)
69	CLOCK_REF	0	Device Time (UTC)
70	CLOCK_REF	1	Time
71	CLOCK_REF	2	Time Offset (h)
72	CLOCK_REF	3	Time Correction (s)
73	CLOCK_REF	4	Model
74	CLOCK_REF	5	Serial Number
75	CLOCK_REF	6	External Time (UTC)
76	CLOCK_REF	7	External Difference (s)
77	CLOCK_REF	8	Source
78	CLOCK_SET	0	Device Time (UTC)
79	CLOCK_SET	1	Time
80	CLOCK_SET	2	Time Offset (h)
81	CLOCK_SET	3	Time Correction (s)
82	CLOCK_SET	4	Model
83	CLOCK_SET	5	Serial Number
84	CLOCK_SET	6	Prior Device Time (UTC)
85	CLOCK_SET	7	Prior Difference (s)
86	CLOCK_SET	8	Source
87	DATA_ERROR	0	Type
88	DATA_ERROR	1	Error
89	DATA_ERROR	2	Page
90	DATA_ERROR	3	Offset
91	DATA_ERROR	4	Description
92	DATA_SOURCE_FILE	0	File Name
93	DATA_SOURCE_FILE	1	UUID
94	DATA_SOURCE_FILE	2	Type
95	DATA_SOURCE_FILE	3	Size
96	DATA_SOURCE_FILE	4	State
97	DEPTH	0	Device Time (UTC)
98	DEPTH	1	Time
99	DEPTH	2	Time Offset (h)
100	DEPTH	3	Time Correction (s)
101	DEPTH	4	Model
102	DEPTH	5	Serial Number
103	DEPTH	6	Depth (m)
104	DEPTH_STATS	0	Device Time (UTC)
105	DEPTH_STATS	1	Time
106	DEPTH_STATS	2	Time Offset (h)
107	DEPTH_STATS	3	Time Correction (s)
108	DEPTH_STATS	4	Model
109	DEPTH_STATS	5	Serial Number
110	DEPTH_STATS	6	Depth Min (m)
111	DEPTH_STATS	7	Depth Max (m)
112	DEPTH_STATS	8	Depth Mean (m)
113	DEPTH_STATS	9	Sample Count
114	DEPTH_STATS	10	Accumulation Period (s)
115	DET	0	Device Time (UTC)
116	DET	1	Time
117	DET	2	Time Offset (h)
118	DET	3	Time Correction (s)
119	DET	4	Model
120	DET	5	Serial Number
121	DET	6	Detection Type
122	DET	7	Full ID
123	DET	8	ID
124	DET	9	Signal Strength (dB)
125	DET	10	Noise (dB)
126	DET	11	Quality Score
127	DET	12	Decoder
128	DET	13	Sensor Value
129	DET	14	Sensor Unit
130	DET_FILTER	0	Filter Name
131	DET_FILTER	1	Details
132	DET_FILTER	2	Rejected Detections
133	DIAG_FAST	0	Device Time (UTC)
134	DIAG_FAST	1	Time
135	DIAG_FAST	2	Time Offset (h)
136	DIAG_FAST	3	Time Correction (s)
137	DIAG_FAST	4	Model
138	DIAG_FAST	5	Serial Number
139	DIAG_FAST	6	Ambient Temperature (deg C)
140	DIAG_FAST	7	Noise (mV)
141	DIAG_FAST	8	Tilt (deg)
142	DIAG_FAST	9	Depth (m)
143	EVENT	0	Device Time (UTC)
144	EVENT	1	Time
145	EVENT	2	Time Offset (h)
146	EVENT	3	Time Correction (s)
147	EVENT	4	Model
148	EVENT	5	Serial Number
149	EVENT	6	Event Type
150	EVENT	7	Event Details
151	EVENT_FAULT	0	Device Time (UTC)
152	EVENT_FAULT	1	Time
153	EVENT_FAULT	2	Time Offset (h)
154	EVENT_FAULT	3	Time Correction (s)
155	EVENT_FAULT	4	Model
156	EVENT_FAULT	5	Serial Number
157	EVENT_FAULT	6	Fault Importance
158	EVENT_FAULT	7	Fault Code
159	EVENT_FAULT	8	Fault Description
160	EVENT_INIT	0	Device Time (UTC)
161	EVENT_INIT	1	Time
162	EVENT_INIT	2	Time Offset (h)
163	EVENT_INIT	3	Time Correction (s)
164	EVENT_INIT	4	Model
165	EVENT_INIT	5	Serial Number
166	EVENT_INIT	6	Prior Device Time (UTC)
167	EVENT_INIT	7	External Time Zone
168	EVENT_INIT	8	Firmware Version
169	EVENT_OFFLOAD	0	Device Time (UTC)
170	EVENT_OFFLOAD	1	Time
171	EVENT_OFFLOAD	2	Time Offset (h)
172	EVENT_OFFLOAD	3	Time Correction (s)
173	EVENT_OFFLOAD	4	Model
174	EVENT_OFFLOAD	5	Serial Number
175	EVENT_OFFLOAD	6	External Time (UTC)
176	EVENT_OFFLOAD	7	External Time Zone
177	EVENT_OFFLOAD	8	HR Total Accepted Detections
178	EVENT_OFFLOAD	9	PPM Total Accepted Detections
179	EVENT_OFFLOAD	10	Memory Remaining (%)
180	EVENT_OFFLOAD	11	Battery Remaining (%)
181	EVENT_OFFLOAD	12	Original File
182	HEALTH_VR2W	0	Device Time (UTC)
183	HEALTH_VR2W	1	Time
184	HEALTH_VR2W	2	Time Offset (h)
185	HEALTH_VR2W	3	Time Correction (s)
186	HEALTH_VR2W	4	Model
187	HEALTH_VR2W	5	Serial Number
188	HEALTH_VR2W	6	Memory Remaining (%)
189	HEALTH_VR2W	7	RTC Time
190	TEMP	0	Device Time (UTC)
191	TEMP	1	Time
192	TEMP	2	Time Offset (h)
193	TEMP	3	Time Correction (s)
194	TEMP	4	Model
195	TEMP	5	Serial Number
196	TEMP	6	Ambient (deg C)
197	TEMP	7	Internal (deg C)
198	TEMP_STATS	0	Device Time (UTC)
199	TEMP_STATS	1	Time
200	TEMP_STATS	2	Time Offset (h)
201	TEMP_STATS	3	Time Correction (s)
202	TEMP_STATS	4	Model
203	TEMP_STATS	5	Serial Number
204	TEMP_STATS	6	Ambient Min (deg C)
205	TEMP_STATS	7	Ambient Max (deg C)
206	TEMP_STATS	8	Ambient Mean (deg C)
207	TEMP_STATS	9	Sample Count
208	TEMP_STATS	10	Accumulation Period (s)
209	DIAG_VR2TX_INTERIM	0	Device Time (UTC)
210	DIAG_VR2TX_INTERIM	1	Time
211	DIAG_VR2TX_INTERIM	2	Time Offset (h)
212	DIAG_VR2TX_INTERIM	3	Time Correction (s)
213	DIAG_VR2TX_INTERIM	4	Model
214	DIAG_VR2TX_INTERIM	5	Pings
215	DIAG_VR2TX_INTERIM	6	Detections
217	DIAG_VR2AR_INTERIM	6	Detections
218	DIAG_VR2AR_INTERIM	5	Pings
219	DIAG_VR2AR_INTERIM	4	Model
220	DIAG_VR2AR_INTERIM	3	Time Correction (s)
221	DIAG_VR2AR_INTERIM	2	Time Offset (h)
222	DIAG_VR2AR_INTERIM	1	Time
223	DIAG_VR2AR_INTERIM	0	Device Time (UTC)
224	DIAG_VR2AR	8	Noise (mV)
225	DIAG_VR2AR	7	Detections
226	DIAG_VR2AR	6	Pings
227	DIAG_VR2AR	5	Serial Number
228	DIAG_VR2AR	4	Model
229	DIAG_VR2AR	3	Time Correction (s)
230	DIAG_VR2AR	2	Time Offset (h)
231	DIAG_VR2AR	1	Time
232	DIAG_VR2AR	0	Device Time (UTC)
233	DIAG_VR2AR	9	Tilt (deg)
234	HEALTH_VR2AR	6	Memory Remaining (%)
235	HEALTH_VR2AR	5	Serial Number
236	HEALTH_VR2AR	4	Model
237	HEALTH_VR2AR	3	Time Correction (s)
238	HEALTH_VR2AR	2	Time Offset (h)
239	HEALTH_VR2AR	1	Time
240	HEALTH_VR2AR	0	Device Time (UTC)
241	HEALTH_VR2TX	6	Memory Remaining (%)
242	HEALTH_VR2TX	5	Serial Number
243	HEALTH_VR2TX	7	RTC Time

Of which 79 are unique.

Peter suggested using the units package: https://r-quantities.github.io/units/ to encode units, and like move2, we could store the unit per column in a constants object: https://gitlab.com/bartk/move2/-/blob/main/R/movebank_constants.R#L87

Originally posted by @PietrH in #254 (comment)

[PietrH]

Will be handy for measurement of fact extension on dwc output, if that comes to be