WebRTC, accumulated updates (#45)

* Implement handling image files

* Gradle cleanup and update the dependencies

* Code cleanup

* Strings extracted to strings.xml

* Update Gradle and Kotlin versions to latest

* added UX/UI to send image files from user to server side

* - Upload files (images) to server
- Code cleaning

* chat_session_signaling event

* New chat_session_form_show event

* Poll Request refactoring

* gitignore update

* Call Activity layout

* API and Demo app impl

* Gradle 7.5  and Kotlin 1.8 updates

* WebRTC library added
WebRTC incoming call implementation - DONE

* WebRTC library added
WebRTC incoming call implementation - DONE

* Change log

---------

Co-authored-by: Alexander Lobastov <58867146+ALobastov@users.noreply.github.com>

Update changelog.md - v 2.0.0

Update CHANGELOG.md

Update CHANGELOG.md

Merge pull request #19 from ServicePattern/feature/json_on_debug

Feature/json on debug

Get rid of unused properties.

Version/artifact

Merge pull request #5 from ServicePattern/bugfix/march_8

Bugfix/march 8