Improve docs for release

[thorinaboenke]

This PR improves documentation completeness, consistency, clarity and formatting.

• tightened descriptions
• corrected and commented codeblocks
• reordered confval entries logically
• removed redundant and legacy content
• moved uv installation instructions to the main section
• correct return value of background commands
• added "required" info to command paramaters
• fixed links
• Added legacy pattern warning to sliver and sliver-session pages
• fixed sys.path in conf.py to point to src/ so autodoc can import modules
• Rewrote attackmate.rst with correct module paths reflecting the actual package structure
• added docstring to baseexecutor (can be expanded in the future)
• added info to python comparison contions