Add Brotli to NGINX

[enoldev]

Fixes #21.

This PR contains:

• A new Dockerfile that uses a multi-stage build to:
  (Stage 1) Compile from source Nginx, get the Brotli and generate the .so files for the modules.
  (Stage 2) By using the official nginx Docker image, the modules are moved to the corresponding directory.
• Changes in the nginx.conf file to enable Brotli, along with the supported types.

NOTE: text/html is always compressed, but I have added it to the supported types, just in case this default behavior changes in the future.

[gruns]

awesome work @enolal826!! 🙌 🙌

1. i cant tell from reading https://github.com/google/ngx_brotli whether responses are always compressed if the response mimetype matches one in brotli_types, or whether responses are only compressed if the response mimetype matches one in brotli_types and the requesting client announced they support brotli with the Content-Encoding: br, ... header

   we only want the latter. the vast majority of browsers support brotli, but ie 11 notably does not https://caniuse.com/brotli

2. add gzip fallback compression when the browser doesn't support brotli. the same mimetype list of compressable filetypes should be used

3. is the default brotli (and gzip) compression level of 6 best for us? probably. but i just want to make sure

NOTE: text/html is always compressed, but I have added it to the supported types, just in case this default behavior changes in the future.

👍

[DiegoRBaquero]

I'd remove text/html because of the annoying warning nginx: [warn] duplicate MIME type "text/html" in /etc/nginx/nginx.conf:52

I don't think they will remove it

[gruns]

any way to deduplicate the gzip_types and brotli_types variables? their values are identical. these:

b5e1cb2#diff-072cd79f6429749707ffb91c13810f82fa3ef6d0d9a8fddaa7c90e6e5c7bc4aeR43-R52

and

2f5182e#diff-072cd79f6429749707ffb91c13810f82fa3ef6d0d9a8fddaa7c90e6e5c7bc4aeR43-R52