Add spymemcached system override properties

[favila]

Adds the following system properties:

• clubhouse.spymemcached.forceProtocol=TEXT (or BINARY)
• clubhouse.spymemcached.forceOpTimeoutMs
• clubhouse.spymemcached.forceOpQueueMaxBlockTimeMs

If any of these are set, they will override the value passed to the corresponding builder method in ConnectionFactoryBuilder. This is for the very specific purpose of forcing datomic to use the ASCII protocol and messing with timeout settings.

Also has some bitrot-fixing commits to get it building again:

• MemcachedConnection imported some packages from outside the java.base module; fortunately it didn't use them, so I just removed them.
• The ant build referenced a now-gone maven server. URL was updated.

[shortcut-integration]

This pull request has been linked to Clubhouse Story #156825: Spymemcached lib with protocol override options.

[pgroudas]

Thanks!