[Python-ideas] Add the brotli & zstandard compression algorithms as modules

Hello everyone, We have many compression algorithms as standard modules, but we lack two important new algorithms: brotli and zstandard. Brotli is an important compression algorithm both for HTTP2 and for compressing/decompressing HTTP responses. ZStandard is another algorithm for compression that can easily beat gzip with a better compression ratio and less compression time. Both are now stable enough and are past the 1.0 mark. Let's include them in the standard library and, of course, make them optional at build time like the rest of our compression modules. What do you think?