Add all 16 *_by_lua_block and 9 *_by_lua directives to crossplane

[xynicole]

Proposed changes

Add all 16 *_by_lua_block and 9 *_by_lua directives to crossplane along with tests.
Add Lua lexer to allow Crossplane to read Lua blocks
Add Lua built
Fix incorrect Lua testdata

How do we parse Lua:
In lexer:

1. Grab everything in the Lua block as a single token and drop the {}. Example:
   content_by_lua_block {some code} will be content_by_lua_block "some code"; "some code" is an argument of directive
2. If a user puts the same argument name as the Lua block directives' name, we will treat it as a normal argument parse. Check if it starts with { which means token depth == 0.
3. If a user puts the same upstream name as the Lua block directives' name, we will treat it as a normal argument parse. Check if the token is a directive
4. Set_by_lua_block has a return value, so we need to additionally check for this directive. Get the return value token first and then obtain the rest of the block token.
5. If a user puts quotes around the Lua directives, we need to skip these quotes.
6. If there are braces inside the Lua block, we should retain them and not remove them as we did in # 1.

In parser (analyzer):
We want to use normal directives way to parse lua block, so
remove ngxConfBlock and change ngxConfNoArgs to ngxConfTake1, for set_by_lua_block change to ngxConfTake2. Just similar to server_name

In builder:
Add ExternalBuild to handle specific directives
Add { } back to the string

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md)

[ornj]

Just commenting for now as I want to take a little more time to look at the lexing of Lua as I'm seeing differences between this implementation and Python other than what I expected.

[ornj]

I'd like to see docstrings on most of the added exported types/functions where it would help the user understand what to do with them (in case it's not obvious) but other than that, lgtm.

[nginx-nickc]

how do we know the "closing quote" is of the same type?
if i do the following, wouldn't this mess things up?

" ' foo ' "

[xynicole]

Good catch, thanks for pointing that out! I added var quoteType string to track if quotes are matched