serve zipped json manifests

[mrcjkb]

This is my attempt to kickstart #225.

Some caveats:

• I've never worked with moonscript, lapis or OpenResty, but based on my analysis of the existing code in applications/manifest.moon and helpers/manifests.moon, this may be enough to add the capability to serve a zipped json manifest?
• I don't know how to generate Lua code from the moonscript code.
• I have been unable to set up a dev environment using the guide in the readme.

The tup command fails with:

  11) [0.072s] views: moonc about.moon                                                                                      
  10) [0.062s] moonc revision.moon                                                                                          
   9) [0.057s] moonc models.moon                                                                                            
   8) [0.049s] moonc lint_config.moon                                                                                       
   7) [0.052s] moonc config.moon                                                                                            
   6) [0.068s] moonc migrations.moon                                                                                        
   5) [0.059s] moonc app.moon                                                                                               
*   4) compile_js views/edit_module.lua > views/edit_module.js                                                              
/bin/sh: line 1: lapis-eswidget: command not found
 *** tup messages ***
 *** Command ID=790 failed with return value 127
*   3) compile_js views/index.lua > views/index.js                                                                          
/bin/sh: line 1: lapis-eswidget: command not found
 *** tup messages ***
 *** Command ID=792 failed with return value 127
*   2) compile_js views/stats.lua > views/stats.js                                                                          
/bin/sh: line 1: lapis-eswidget: command not found
 *** tup messages ***
 *** Command ID=794 failed with return value 127
 [                                          ETA~=<1s Remaining=2   Active=0                                           ]  98%
 *** tup: 3 jobs failed.

(this is after setting up the luarocks path).

• This would probably need some tests, but without being able to set up a dev environment,
  I don't want to risk wasting too much effort.

Perhaps someone who is more familiar with this codebase is willing to pick this up if it's going in the right direction?

[mrcjkb]

I guess a "manifest.json.zip" request will be parsed as format = "zip"?

[mrcjkb]

Actually, I think /manifest(-:a.:b)(.:format) will also successfully parse manifest-5.1.json.zip.

[mrcjkb]

@leafo is there anything I can do to move this forward?

Downloading zipped Lua manifests isn't an option for me until the luajit bug that prevents loading large tables is fixed. And unzipped json manifests take too long to download.