### Background
Follow up after merging https://github.com/Significant-Gravitas/AutoGPT/pull/7054, old plugins will no longer be used.
### Changes 🏗️
- Removed all dead code needed to load and use plugins.
- Removed `auto-gpt-plugin-template` dependency
- Removed `rev=` from `autogpt-forge` dependency (the set `rev` had incompatible `duckduckgo-search` versions)
- Kept `--install-plugin-deps` CLI option and dead code associated (may be needed for new plugins)
- Modify check_requirements.py to correctly handle optional dependencies
- Skip optional dependencies when iterating through dependence group dependencies in check_requirements.py
* Fix all but one flake8 linting errors
* Remove unused imports
* Wrap strings that are too long
* Add basic autogpts/autogpt/.flake8
* Delete planning_agent.py
* Delete default_prompts.py
* Delete _test_json_parser.py
* Refactor the example function call in AgentProfileGeneratorConfiguration from a string to an object
* Rewrite/update docstrings here and there while I'm at it
* Minor change to the description of the `open_file` command
* Use `user-agent` from config in web_selenium.py
* Delete hardcoded ABILITIES from core/planning/templates.py
* Delete duplicate and superseded test from test_image_gen.py
* Fix parameter definitions in mock_commands.py
* Delete code analysis blocks from test_spinner.py, test_url_validation.py
* Removed `autogpt.llm.base` and `autogpt.llm.utils`
* `core` does things async, so `Agent.think()` and `Agent.execute()` are now also async
* Renamed `dump()` and `parse()` on `JSONSchema` to `to_dict()` and `from_dict()`
* Removed `MessageHistory`
* Also, some typo's and linting fixes here and there
Reinier van der Leer
Krzysztof Czerwinski
Reinier van der Leer
Merwane Hamadi