feat: improve generation of bundled assets (#8143)

- Replace the current vfsgen with our own bindata generator.
- zstd is used instead of gzip. This reduces the size of the resulting binary by 2MiB, the size of the bundled assets were thus reduced from 13MiB to 11MiB.
- If [the browser accepts zstd encoding](https://caniuse.com/zstd), then the compressed bytes can be served directly, otherwise it falls back to being compressed by gzip if it's not disabled via `[server].ENABLE_GZIP`
- The compression and decompression speed is roughly 4 times faster.
- The generated filesystem is now of type `fs.Fs` instead of `http.FileSystem`, this slightly simplifies the generated code and
handling of the assets.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8143
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

go.sum

@@ -384,8 +384,6 @@ github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
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 github.com/libdns/libdns v1.0.0-beta.1/go.mod h1:4Bj9+5CQiNMVGf87wjX4CY3HQJypUHRuLvlsfsZqLWQ=
-github.com/lunny/vfsgen v0.0.0-20220105142115-2c99e1ffdfa0 h1:F/3FfGmKdiKFa8kL3YrpZ7pe9H4l4AzA1pbaOUnRvPI=
-github.com/lunny/vfsgen v0.0.0-20220105142115-2c99e1ffdfa0/go.mod h1:JEfTc3+2DF9Z4PXhLLvXL42zexJyh8rIq3OzUj/0rAk=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/mailru/easyjson v0.9.0 h1:PrnmzHw7262yW8sTBwxi1PdJA3Iw/EKBa8psRf7d9a4=
 github.com/mailru/easyjson v0.9.0/go.mod h1:1+xMtQp2MRNVL/V1bOzuP3aP8VNwRW55fQUto+XFtTU=
@@ -504,8 +502,6 @@ github.com/santhosh-tekuri/jsonschema/v6 v6.0.2/go.mod h1:JXeL+ps8p7/KNMjDQk3TCw
 github.com/serenize/snaker v0.0.0-20171204205717-a683aaf2d516/go.mod h1:Yow6lPLSAXx2ifx470yD/nUe22Dv5vBvxK/UK9UUTVs=
 github.com/sergi/go-diff v1.4.0 h1:n/SP9D5ad1fORl+llWyN+D6qoUETXNZARKjyY2/KVCw=
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-github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c h1:aqg5Vm5dwtvL+YgDpBcK1ITf3o96N/K7/wsRXQnUTEs=
-github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c/go.mod h1:owqhoLW1qZoYLZzLnBw+QkPP9WZnjlSWihhxAJC1+/M=
 github.com/sirupsen/logrus v1.7.0/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=