CLDR-14162 add first version of file (#739)

(cherry picked from commit 21cf8e8)

common/properties/external_data_versions.tsv

@@ -0,0 +1,14 @@
+#Data	Date	Version Info	File
+Factbook data	2020-08-28	Recorded when downloaded	factbook_population.txt, etc.
+ISO 636 (language) data	2020-01-30	Date in YYYYMMDD	iso-639-3-version.tab, etc.
+ISO currency data	2019-05-19	Recorded when downloaded	iso4217raw.txt
+ISO subdivision codes	2020-02-24	Recorded when downloaded	not stored
+ISO subdivision names	2019-02-24	Recorded when downloaded	not stored
+Language Groups	2017-09-24	Recorded when downloaded	childToParent.tsv, etc
+Timezone IDs (tzdb)	2020-07-07	Recorded when downloaded	africa, etc.
+Top level domains	2020-08-22	Date at top	tlds-alpha-by-domain.txt
+UN member states	2019-05-19	Recorded when downloaded	eu_member_states_raw.txt
+UN literacy data	2020-08-01	Date at top	un_literacy.csv
+UN member states	2019-05-19	Date at top	un_member_states_raw.txt
+Worldbank data	2020-08-18	Date at bottom	world_bank_data.csv
+NIST unit data	2020-03-10	Recorded when downloaded	nistBaseUnits.txt, etc