User friendly manual network configuration

[vi7]

Description:

1. Add ability for user friendly IP address override without the need to touch User_config.h
2. Add DNS server option for ESP WiFi STA

NOTE: Tested on Wemos D1 mini (ESP8266) ONLY, unfortunately I do not have a possibility to test on Arduino and ESP32

Checklist:

• The pull request is done against the latest development branch
• Only one feature/fix was added per PR and the code change compiles without warnings
• I accept the DCO.

[DigiH]

Testing on ESP32s and ESP8266s, including Avatto S06 IR and Sonoff RF Bridge - running smoothly.

[DigiH]

@vi7

Could you also add a paragraph about this in the documentation? I think it would fit nicely as a separate NOTE after the NOTE

::: warning Note Adding manual WiFi and MQTT credentials …

in

https://github.com/1technophile/OpenMQTTGateway/blob/development/docs/upload/builds.md

Thanks

[1technophile]

Also adding the macros into the following environment: [env:esp32dev-all-test]
So that they get tested

[vi7]

@DigiH @1technophile thanks guys for checking this, docs updated as well.

[DigiH]

@vi7

Thanks for the Docs update. Could you also add the network build_flags to the [env:esp32dev-all-test] environment, as @1technophile mentioned? This assures constant tests runs with these flags, to avoid future possible regressions.

https://github.com/1technophile/OpenMQTTGateway/blob/development/environments.ini#L51

Thanks

[vi7]

@DigiH done, pls let me know if network parameters (IP, mask etc.) for the test env should be different

[1technophile]

Thanks!