chore(sources/dataplex)!: Renaming changes across all the files related to Dataplex Toolbox

[anikasharma03]

Description

Perform a full rename across files and directories related to the Dataplex Toolbox . This wide-scale refactoring is needed to ensure consistency across the entire codebase and documentation.

Key Changes

File and Directory Renaming:

Moved and renamed all directories and files associated with the dataplex implementation to follow the new naming convention (e.g., in internal/tools/, internal/sources/, and tests/).

Documentation Updates:

Updated references in README.md, integration guides, and other documentation files to reflect the new component naming.

Code Refactoring:

Updated internal references, variable names, and configuration keys to match the new naming standard while maintaining functional compatibility.

Test Updates:

Renamed test files and updated test cases to ensure they correctly validate the renamed components.

PR Checklist

Thank you for opening a Pull Request! Before submitting your PR, there are a
few things you can do to make sure it goes smoothly:

• Make sure you reviewed
  CONTRIBUTING.md
• Make sure to open an issue as a
  bug/issue
  before writing your code! That way we can discuss the change, evaluate
  designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)
• Make sure to add ! if this involve a breaking change

🛠️ Fixes #2956

[gemini-code-assist]

Code Review

This pull request renames "Dataplex" to "Knowledge Catalog" across the entire repository, including CI configurations, documentation, internal Go packages, and integration tests. The feedback provided focuses on maintaining consistent naming conventions in the documentation and fixing a minor typo in the description of the search aspect types tool.

[Yuan325]

Might be good to update the project env var as well so users are not confused (having to use type as "knowledge-catalog" but env var with the "dataplex" name). Please update it across the docs~

we're missing updates on these files:

• .github/CODEOWNERS - folder name (we can keep the mdb group as is for now)
• .github/blunderbuss.yml - update the label name (can keep the group as is)
• .github/labels.yaml

Will dataplex be updating the official cloud docs page link? e.g. https://cloud.google.com/dataplex? If yes, we might want to update that as well. seems like some of bigquery doc that points towards that too.

Thank you!

[Yuan325]

/gcbrun