Memcached: Update to v1.6.37

[mreid-tt]

Description

This PR includes the following:

1. Update Memcached to v1.6.37.
2. Move PHPMemcachedAdmin to separate package.
3. Add PHP profiles for DSM 6.

Fixes #6392

Checklist

• Build rule all-supported completed successfully
• New installation of package completed successfully
• Package upgrade completed successfully (Manually install the package again)
• Package functionality was tested
• Any needed documentation is updated/created

Type of change

• New Package
• Package update

[mreid-tt]

Hello @hgy59, this package update is ready to merge. I’d like your thoughts on splitting the original package into two components. For lower-powered NAS units, an integrated PHP-based admin panel might introduce unnecessary overhead, and some users may prefer to manage their cluster from a single node while others simply provide caching services. Also, the PHP-based admin panel seems no longer maintained, so freezing it in a separate application would let the main cache module receive updates independently. Please let me know if you have any concerns — this is my first time splitting a package.