[Feature] Add Workerman session handler

Actually exist File and Redis SessionHandler.

Try to add one using only Workerman, will be fast and don't have dependencies.

Redis and Memcached use Ram, so we can do the same with Workerman.
The same that the Worker manage connections, we can have a SessionHandler that manage the sessions in RAM.

Later we will try to optimize the size used.

Start by reviewing the existing File and Redis SessionHandler implementations mentioned in the issue. Then determine how a Workerman-only handler should manage sessions in worker RAM without external dependencies. Done means a working in-memory session handler with behavior comparable to the existing handlers; memory-size optimization is explicitly deferred.

Written by the indexing model from the issue text.