Support new encryption options

[LuisMunozVillarreal]

This change adds support for all the new encryption options (docs):

1. true
2. yes
3. mandatory
4. strict
5. optional
6. false
7. no

Plus True and False for backward compatibility. Which ultimately gets converted into Yes and No, respectively.

[LuisMunozVillarreal]

This change passed tests on my fork while using this repo's docker images:

• Unit tests: https://github.com/LuisMunozVillarreal/dbt-sqlserver/actions/runs/16273179409
• Integration: https://github.com/LuisMunozVillarreal/dbt-sqlserver/actions/runs/16273179406

Last commit fails because I reverted the workflows to use the current repo images and my fork doesn't have the necessary images