Fix composer to installable version. Update documentation

[mtangoo]

Q	A
Is bugfix?	✔️
New feature?	❌
Breaks BC?	❌
Fixed issues	294

[what-the-diff]

PR Summary

• Resolved Version Conflict Issue
  The compatibility problem with the package yiisoft/yii2-apidoc in the composer.json file has been addressed by updating it to the version ~3.0.6.

• Updated README with Executable Location Information
  The README file is now enriched with a note about the location of the executable files, specifically in the /vendor/bin directory. This recommendation aims to simplify access to these executable files by switching to the given directory.

• Enriched README with Command Output Descriptions
  The README file now includes the output descriptions for the apidoc help api and apidoc help guide commands. This will provide clearer guidance for users on what these commands do.