Add two new ports archivers/php-zstd and archivers/php-lz4

php-zstd is a PHP extension for zstd compresssion algorithm
https://github.com/kjdev/php-ext-zstd

php-lz4 is a PHP extension for the lz4 compression algorithm
https://github.com/kjdev/php-ext-lz4

PR: 236742
Submitted by: Paavo-Einari Kaipila <pkaipila@gmail.com>