refactor: AutoGPT Platform Stealth Launch Repo Re-Org (#8113)

Restructuring the Repo to make it clear the difference between classic autogpt and the autogpt platform:
* Move the "classic" projects `autogpt`, `forge`, `frontend`, and `benchmark` into a `classic` folder
  * Also rename `autogpt` to `original_autogpt` for absolute clarity
* Rename `rnd/` to `autogpt_platform/`
  * `rnd/autogpt_builder` -> `autogpt_platform/frontend`
  * `rnd/autogpt_server` -> `autogpt_platform/backend`
* Adjust any paths accordingly

.gitignore

@@ -1,7 +1,7 @@
 ## Original ignores
 .github_access_token
-autogpt/keys.py
-autogpt/*.json
+classic/original_autogpt/keys.py
+classic/original_autogpt/*.json
 auto_gpt_workspace/*
 *.mpeg
 .env
@@ -157,7 +157,7 @@ openai/
 CURRENT_BULLETIN.md
 
 # AgBenchmark
-agbenchmark/reports/
+classic/benchmark/agbenchmark/reports/
 
 # Nodejs
 package-lock.json
@@ -170,4 +170,4 @@ pri*
 ig*
 .github_access_token
 LICENSE.rtf
-rnd/autogpt_server/settings.py
+autogpt_platform/backend/settings.py