cleanup: remove unused files/dirs from the top level (#446)

## Summary
cleaning up top level dir 

## Checklist
- [ ] Added Unit Tests
- [x] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Chores**
- Refined version control and build settings by updating ignored paths
and tool versions.
- Removed obsolete internal configurations, tooling, and Docker build
files for a cleaner project structure.
- **Documentation**
  - Updated installation guidance links for clearer setup instructions.
- Eliminated legacy contributor, governance, and quickstart guides to
reduce clutter.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: nikhil-zlai

.gitignore

@@ -103,4 +103,4 @@ releases
 # Bazel mod files (currently unused)
 MODULE.bazel*
 
-/authoring/vscode/node_modules
+/plugins/vscode/node_modules

.plugin-versions

@@ -1,8 +1,6 @@
 asdf-plugin-manager  https://github.com/asdf-community/asdf-plugin-manager.git  b5862c1
 bazelisk             https://github.com/josephtate/asdf-bazelisk.git            9b1cd87
 gcloud               https://github.com/jthegedus/asdf-gcloud.git               00cdf06
-java                 https://github.com/halcyon/asdf-java.git                   0ec69b2
 python               https://github.com/danhper/asdf-python.git                 a3a0185
-sbt                  https://github.com/lerencao/asdf-sbt                       53c9f4b
 scala                https://github.com/asdf-community/asdf-scala.git           0533444
 thrift               https://github.com/alisaifee/asdf-thrift.git               fecdd6c

.scalafix.conf

@@ -1,11 +1,6 @@
-java corretto-11.0.25.9.1
-    corretto-11.0.25.9.1
-    corretto-17.0.9.8.1
 scala 2.12.18
 asdf-plugin-manager 1.4.0
-sbt 1.8.2
 python
-    3.7.17
     3.11.0
 gcloud 507.0.0
 bazelisk 1.25.0