Improve description in readme and extract internals

[vjik]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (5a66792) 96.86% compared to head (045fc37) 96.86%.

:exclamation: Current head 045fc37 differs from pull request most recent head 67e536f. Consider uploading reports for the commit 67e536f to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #192 +/- ## ========================================= Coverage 96.86% 96.86% Complexity 79 79 ========================================= Files 9 9 Lines 255 255 ========================================= Hits 247 247 Misses 8 8 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[what-the-diff[bot]]

PR Summary

• Updated README.md File The main project document was updated to reflect recent changes and provide better information on Yii Console package. This includes an improved description, list of new features, updated installation command, and a link to a deeper section on how Yii Console works.

• Updated composer.json File Composer, our dependency management tool, had its core file modified to better describe the Yii Console package.

• Addition of internals.md in Docs A new document was added that deep dives into the technical underpinnings of our package. This offers insight into unit testing, examining code mutations, static code analysis, style guide preferences, dependencies, and how the Composer Requirement Checker operates.