Also:
* Revamp kotlin-native/README.md a bit: make it more up-to-date,
  add useful links
* Remove "composite build" section from ReadMe.md:
  it was used for Kotlin + Kotlin/Native composite;
  this is no longer required.

Co-authored-by: NAlexander Udalov <udalov@users.noreply.github.com>

Added a section about Multiplatform Capabilities, highlighted KMM

Now TeamCity badge points on archive configuration.
This PR make it to point on relevant Compiler Build

Update usages of old IDEA versions in readme

Update to better describe first time import of project. Changed URL for up for grabs to filter to only show Open issues.

Otherwise this text appears in numerous pull requests and contributors
do not understand what to do with it

This is to provide some guidance for PRs like: https://github.com/JetBrains/kotlin/pull/1769

`qualify` -> `quality`

* Fix a couple of typos
- In the main ReadMe.md
- In onEach template's doc

* Update generated source code

- Actualize build requirements and steps
- Extract Gradle plugin readme to the corresponding folder
- Rewrite Libraries and Maven Tools readme

#KT-20995 Fixed