extra info on zstd, zlib, lzma

[checktext00]

add extra info about zstd, about decompression speeds for zstd,zlib,lzma, and about using zstd and zlib with the chdman create... commands (some info from #7402 (comment))

[cuavas]

Description of option values is definitely not the right place for the suggestions.

[crashGG]

The decompression speed of zstd is fast, but not as fast as expected. A simple test:
Use single algorithm to compress a DVD iso with almost no duplicate data
chdman createdvd -c zstd -i sample.iso -o zstd.iso
chdman craatedvd -c zlib -c zstd -i sample.iso -o zlib.chd
chdman craatedvd -c flac -c zstd -i sample.iso -o flac.chd
chdman craatedvd -c haff -c zstd -i sample.iso -o haff.chd
chdman craatedvd -c lzma -c zstd -i sample.iso -o lzma.chd

Then use chdman verify to decompress 5 chd files with script to calculate the time difference (accurate to milliseconds) and divide it by the file size to get the decompression speed of 5 algorithms. According to my hardware（amd 7840h）, flac 110M/s ,huff 87M/s, zlib 97M/s, zstd 115.7M/s lzma 24.6M/s