[lldb/docs] Breakdown python reference into multiple files (#158331)
This pages improve the LLDB website documentation readability and
discoverability by breaking down the very long python-reference page
into multiple subpages each explaining a specific topic.
The long term goal is to have tutorials for every scripting extension.
This also converts the pages to markdown, since it's easier to write.
Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>