Accept `locale` parameter for `/schema`

[dstillman]

And don't return the other locales, to reduce data transfer for web-library and zbib

1. Replace scripts/update-gz in https://github.com/zotero/zotero-schema/ with a (Python?) script that pre-generates a whole bunch of gzipped files, one for each locale
2. Add a hard-coded list of known locales in .htaccess, falling back to the full file

[dstillman]

dataserver/htdocs/.htaccess

Lines 22 to 38 in 5fba6e4

	#
	# Serve pre-compressed schema file from zotero-schema submodule
	#
	# https://httpd.apache.org/docs/2.4/mod/mod_deflate.html#precompressed
	#
	RewriteCond "%{HTTP:Accept-Encoding}" "gzip"
	RewriteRule ^schema$ zotero-schema/schema.json.gz [QSA]
	# Serve correct content type, and prevent mod_deflate double gzip.
	RewriteRule ^zotero-schema/schema\.json.gz$ - [T=application/json,E=no-gzip:1]
	<Files schema.json.gz>
	# Serve correct encoding type
	Header append Content-Encoding gzip
	# Force proxies to cache gzipped & non-gzipped schema file separately
	Header append Vary Accept-Encoding
	# CORS
	Header set Access-Control-Allow-Origin "*"
	</Files>

We only make gzipped requests from our own software (and if we notice someone else not doing that, we should probably tell them to), so we probably don't need to worry about the locale parameter for non-gzipped requests — it can just return the regular JSON file.