Use self-hosted fonts from staticbrainz.org

[amCap1712]

Keeping in mind ORG-51, we decided to self host google fonts on staticbrainz.org. The fonts themselves are now available on SB but we also need to modiffy the css @import urls and link to fonts.google.com.

TODO

• staticbrainz.org currently does not add CORS headers for localhost so the fonts cannot be loaded in dev setup. This is not good so we should wait to fix that before merging.
• Check there are no other usages in LB which need to be updated.
• Check fonts work properly across browsers and versions.

[alastair]

As we mentioned in IRC, musicbrainz hosts static assets from the dev server during local development. We could modify our get_static_path to handle both of these cases so that we don't need CORS headers for localhost.