feat: Specific imports for convert

[mutahhir]

Related issue

Fixes #2647

Description

This PR adds support for specific imports when using cdktf convert. This has the following benefits. Firstly the code is more idomatic, and what we recommend people to write, rather than doing a default import of entire providers. Secondly, this unlocks code generation that works well with C# which does not have star imports.

This also couples with #2935 that updates the imports to the correct destination path per language

Checklist

• I have updated the PR title to match CDKTF's style guide
• I have run the linter on my code locally
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation if applicable
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works if applicable
• New and existing unit tests pass locally with my changes

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days. This helps our maintainers find and focus on the active issues. If you've found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.