Inference to cloud handler

[ZoranPandovski]

Description

This PR changes the mindsdb inference handler as mindsdb cloud. The handler, README and docs are updated

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 requires a documentation update

Additional Media:

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.

[martyna-mindsdb]

Shall we update the handler folder name to "mindsdb/integrations/handlers/mindsdb_cloud_handler (instead of "mindsdb_cloud")?

[ZoranPandovski]

Actually, the name doesn't make any change since we are not releasing them. I just checked and it is the same in all handlers, so we may decide on keeping only the name without _handler

[MinuraPunchihewa]

@ZoranPandovski The existing changes look good, but I think we will have to update the unit tests in tests/unit/ml_handlers/test_mindsdb_inference.py as well?

[ZoranPandovski]

Moving this to Draft as discussed