www/elinks: improve support for various available (de)compressors

- Build with zlib support (looking at the commit history, it is unclear
  why it was disabled in the first place)
- Add BROTLI, LZMA, and ZSTD options; disable the latter by default as
  it is being described as experimental in the configure script
- Drop ICONV option as it typically does not pull additional dependency
  but is required for the BROTLI option (at least)
- While here, sort the OPTIONS_* lists alphabetically as appropriate