[New Feature] Add command SwitchText to change switches names in JSON

[barbudor]

Description:

New feature introduce a new command SwitchText to replace the default "Switchn" name in the JSON messages by a custom meaningful text. Usefull when "Switch" inputs are used as general purpose digital input sensor (such door state, battery charging status...)
The command and associated code is inserted only if USE_SWITCHTEXT is defined.
When USE_SWITCHTEXT is not defined the only impact is 8 (MAX_SWITCHES) zero-length strings are reserved
into Settings.text_pool.
When a binary with USE_SWITCHTEXT is loaded for the 1st time, each SET_SWITCH_TXT<n> text setting is a zero-length
string. The JSON messages then use the default "Switchn" name.
Once SwitchText<n>has been used to defined a name, it is saved in the settings and further JSON messages will use
the custom name.
If a binary without USE_SWITCHTEXT is loaded after some SwitchText<n> have been defined, they remains as-is in the
text setting pool and JSON messages revert to legacy "Switchn" names.
SwitchText command syntax is similar to the StateText command:

• SwitchText : returns all 8 SwitchText values
• SwitchText<x> : returns the matching SwitchTextvalue (where <x> is a number between 1 and 8)
• SwitchText<x> <text> : defines <text> as the new name for "Switchx"

Checklist:

• The pull request is done against the latest dev branch
• Only relevant files were touched
• Only one feature/fix was added per PR.
• The code change is tested and works on Tasmota core ESP8266 V.2.7.4.5
• The code change is tested and works on core ESP32 V.1.12.2
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass

[barbudor]

A little demo of the JSON when using this feature with 8 switches defined :

20:08:23 MQT: tele/dev-4119/SENSOR = {"Time":"2020-10-31T20:08:23+01:00","Charging":"ON","Charged":"ON","FrontDoorOpen":"ON","RearDoorOpen":"ON","FridgeDoorOpen":"ON","FreezerDorrOpen":"ON","GarageDoorOpen":"ON","YetAnotherStupidSwitchText":"OFF"}

[arendst]

Nice thx. Will soon merge after my chk

[arendst]

Thx. Implemented my way.

[barbudor]

Thanks @arendst
Was the main reason for doing "your way" being that I didn't make the changes in the most appropriate place ?
Regards

[arendst]

You almost had the most appropriate way ;-) but there were a few functions not needed. Also by consolidating the name decision in one function made both status and rule code less explosive.

Thx for your idea.