Add transformations support

[fivetran-aleksandrboldyrev]

No description provided.

[beevital]

Great work! Thank you.
But for QDM package transformation user can't update transformation_config.package_name and transformation_config.connection_ids - these are required on creation immutable fields.

They aren't marked as required in schema as there's more complex requirement: user must specify either one of these params on creation.

Basically these fields should be marked as "force new" in schema as changing leads to new transformation package creation.

Also I'd suggest to add more validations:

• check if plan contains only fields related to particular transformation type (you can't set steps for QDM, but now it's possible and will lead to issues)
• check for QDM if connection_ids are set or package_name specified.

For sure API will return error response on apply, but for example if I setup steps for qdm transformation - terraform apply will be successful, but then the state will be inconsistent (API won't return steps value back is it just ignored)