Update OpenResty typedefs, annotations, and configuration

[flrgh]

This is a continuation of the work I started for updating OpenResty library types. I've split it up into separate commits, but it's still a pretty large changeset. Let me know if I need to re-structure the commits to make things easier for review+merge.

Most of the changes here are as such:

• Adding missing annotations, typedefs, and docstrings to many files
• Cleanup of the global namespace by ensuring that module tables are local-ized
• Cleanup of excessively namespaced variable names so that hover/help text is more concise

I did a lot of editing to ngx.lua in particular:

• Remove extraneous markdown cruft from function docstrings
• Reorganize contents for easier editing (group similar functions and fields together)
• Added some helper enum-like aliases (ngx.log.level/ngx.http.method/ngx.http.status_code)

I also updated the config.lua file for OpenResty:

• Added new file and word matchers
• Added ngx as a global var (not sure if this is necessary)

I haven't applied these efforts to all files yet, so there is still much work to be done to make the OpenResty typedefs awesome, but I think this is good progress :)

[sumneko]

No problem, thanks for your work!