Clickhouse improvments

[ZoranPandovski]

This PR verifies the CH Integration by:

• Providing correct structure for README and Docs + troubleshooting guide
• Adds unit tests and lints the code
• Runs coveralls on CI push action
• Removes unused QA file

Type of change

(Please delete options that are not relevant)

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ⚡ New feature (non-breaking change which adds functionality)
• 📢 Breaking change (fix or feature that would cause existing functionality not to work as expected)
• 📄 This change has a documentation update

Checklist:

• My code follows the style guidelines(PEP 8) of MindsDB.
• I have appropriately commented on my code, especially in complex areas.
• Necessary documentation updates are either made or tracked in issues.
• Relevant unit and integration tests are updated or added.

[MinuraPunchihewa]

@ZoranPandovski This looks good to me. Are we going to be adding integration similar to the ones we have for Postgres?