[WIP] Add support for runtime configuration of network parameters

[manchoz]

This PR is for adding support for configuration of network parameters (SSID/Username/Password for WiFi and APN/Username/Password for GSM/NB) at runtime, to allow the user to (re)configure these parameters after the Connection Handler has been constructed.

[github-actions[bot]]

Memory usage change @ea6affc8e7774c5b36b89542ade04f122107df67

FQBN	Flash Usage	RAM For Global Variables
arduino:samd:mkr1000	0	0
arduino:samd:mkrgsm1400	0	0
arduino:samd:mkrnb1500	0	0
arduino:samd:mkrwan1300	0	0
arduino:samd:mkrwan1310	0	0
arduino:samd:mkrwifi1010	0	0
arduino:samd:nano_33_iot	0	0
esp8266:esp8266:huzzah	0	0

[aentinger]

I'll just want you to know that I'll integrate the connection handling functionality back with ArduinoIoTCloud after OTA is complete. Then I'll be also on the subject of proper connect/disconnect sequences for "mostly disconnected" devices.

[manchoz]

Will this PR be still relevant? May I go ahead and add the changes to the other classes?

[aentinger]

From what I see this PR probably will still be relevant, I mean you are basically adding a couple of setters. Once disconnect/reconnect is possible we'll need to really store the login data so that's okay. I don't know what you have in mind to adding to other classes but it it's setters to then please go ahead.

[github-actions[bot]]

Memory usage change @ 36e31aae5bfde3b366d1f0b27a47c69df1efe88c

Board	flash	RAM for global variables
arduino:samd:mkr1000	0 - 0	0 - 0
arduino:samd:mkrgsm1400	0 - 0	0 - 0
arduino:samd:mkrnb1500	0 - 0	0 - 0
arduino:samd:mkrwan1300	0 - 0	0 - 0
arduino:samd:mkrwan1310	0 - 0	0 - 0
arduino:samd:mkrwifi1010	0 - 0	0 - 0
arduino:samd:nano_33_iot	0 - 0	0 - 0
esp8266:esp8266:huzzah	0 - 0	0 - 0

Click for full report table

Board|examples/ConnectionHandlerDemo
flash|examples/ConnectionHandlerDemo
RAM for global variables -|-|- arduino:samd:mkr1000|0|0 arduino:samd:mkrgsm1400|0|0 arduino:samd:mkrnb1500|0|0 arduino:samd:mkrwan1300|0|0 arduino:samd:mkrwan1310|0|0 arduino:samd:mkrwifi1010|0|0 arduino:samd:nano_33_iot|0|0 esp8266:esp8266:huzzah|0|0

Click for full report CSV

``` Board,examples/ConnectionHandlerDemo
flash,examples/ConnectionHandlerDemo
RAM for global variables arduino:samd:mkr1000,0,0 arduino:samd:mkrgsm1400,0,0 arduino:samd:mkrnb1500,0,0 arduino:samd:mkrwan1300,0,0 arduino:samd:mkrwan1310,0,0 arduino:samd:mkrwifi1010,0,0 arduino:samd:nano_33_iot,0,0 esp8266:esp8266:huzzah,0,0 ```

[github-actions[bot]]

Memory usage change @ c86cd2b8e086b4cf46e3f6668afd74ff7f93b092

Board	flash	RAM for global variables
arduino:samd:mkr1000	0 - 0	0 - 0
arduino:samd:mkrgsm1400	0 - 0	0 - 0
arduino:samd:mkrnb1500	0 - 0	0 - 0
arduino:samd:mkrwan1300	0 - 0	0 - 0
arduino:samd:mkrwan1310	0 - 0	0 - 0
arduino:samd:mkrwifi1010	0 - 0	0 - 0
arduino:samd:nano_33_iot	0 - 0	0 - 0
esp8266:esp8266:huzzah	0 - 0	0 - 0

Click for full report table

Board|examples/ConnectionHandlerDemo
flash|examples/ConnectionHandlerDemo
RAM for global variables -|-|- arduino:samd:mkr1000|0|0 arduino:samd:mkrgsm1400|0|0 arduino:samd:mkrnb1500|0|0 arduino:samd:mkrwan1300|0|0 arduino:samd:mkrwan1310|0|0 arduino:samd:mkrwifi1010|0|0 arduino:samd:nano_33_iot|0|0 esp8266:esp8266:huzzah|0|0

Click for full report CSV

``` Board,examples/ConnectionHandlerDemo
flash,examples/ConnectionHandlerDemo
RAM for global variables arduino:samd:mkr1000,0,0 arduino:samd:mkrgsm1400,0,0 arduino:samd:mkrnb1500,0,0 arduino:samd:mkrwan1300,0,0 arduino:samd:mkrwan1310,0,0 arduino:samd:mkrwifi1010,0,0 arduino:samd:nano_33_iot,0,0 esp8266:esp8266:huzzah,0,0 ```

[ubidefeo]

@aentinger do you still want to bring this library back into IoT Cloud? if this is the case I'm gonna have to fork it because I really use it :D

[aentinger]

No, I gave up on that for now @ubidefeo . There are bigger fish to fry and right now Arduino_ConnectionHandler is doing it's job.

[CLAassistant]

All committers have signed the CLA.