Ability to encrypt user data

[StpMax]

Description

Encrypt integrations connection args and tabs content.

Not encrypted tab structure is like:

{
    "index": 1,
    "name": "tab name",
    "content": "select * from table"
}

Encrypted tab structure is like:

{
    "index": 1,
    "name": "tab name",
    "_encrypted_content": "t1aiVMMh3VMH8HEaloUsqcPwjCXpZpJf9t"
}

Not encrypted connection args is like:

{
    "user": "username",
    "password": "123456"
}

Encrypted connection args is like:

{
    "_mindsdb_encrypted_data": "4U+DeMQCl2iaV+say1yiFNCVH+cpwNpXzwwYfmkg",
    "keys": ["user", "password"]
}

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

Verification Process

To ensure the changes are working as expected:

• Test Location: Specify the URL or path for testing.
• Verification Steps: Outline the steps or queries needed to validate the change. Include any data, configurations, or actions required to reproduce or see the new functionality.

Additional Media:

• I have attached a brief loom video or screenshots showcasing the new functionality or change.

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.

[ea-rus]

do we need this warning on every request?

[ea-rus]

what if encryption_enabled is set ctx.encryption_key_bytes is empty?