Berry webserver_async

[s-hadinger]

Description:

Add Berry webserver_async for features like real-time logs or real-time debugging information.

[Edit]
Flash increase: 8.8KB only if USE_BERRY_DEBUG is defined

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.7
• The code change is tested and works with Tasmota core ESP32 V.3.0.2
• I accept the CLA.

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

[Jason2866]

Mhh, nearly 11kb. Needs this feature to be solidified? One of the great Berry benefits is not to add not often used/needed features to every build.

Wouldn't it be possible to do as compile time option?

• Standard build leave everything as it is currently.
• Debug build, embedding Berry Async Web Server

[s-hadinger]

Let's put on hold for now, I have some more optimization, and will put it only with USE_BERRY_DEBUG

[s-hadinger]

webserver_async now reduced to 9KB, and only included if USE_BERRY_DEBUG is enabled