Look for all accepted encodings for precompressed files but keeping the quality ordering

[kobutri]

Description

Instead of only looking for a precompressed file matching the preferred encoding, I check for all accepted encodings.

Related Issue

#438

Motivation and Context

Crome accepts brotli and brotli is generally superior to gzip, but Chrome always lists gzip first in the Accept-Encoding header.
#438

How Has This Been Tested?

I created a new brotli compressed index.html.br and created a test that accepts deflate, br. Because of this change the index.html.br will be returned, where previously no compressed file would be returned.

Screenshots (if appropriate):

[semanticdiff-com]

Review changes with SemanticDiff.

Analyzed 4 of 5 files.

Overall, the semantic diff is 51% smaller than the GitHub diff.

	Filename	Status
✔️	src/compression.rs	Analyzed
✔️	src/compression_static.rs	88.02% smaller
✔️	tests/compression_static.rs	Analyzed
✔️	tests/dir_listing.rs	3.52% smaller
❔	tests/fixtures/public/404.html.br	Unsupported file format

[joseluisq]

The idea is not bad. In fact, it helps SWS to decide better which file to serve.
FYI I just fixed syntax issues and improved the test a bit.

Thanks!