[NEW] Support regex filtering

[hpatro]

The problem/use-case that the feature addresses

Support regex filtering for the API(s) which currently support glob based matching. This will provide user to filter out keys/channels based on the requirements and not be limited by the glob support.

Description of the feature

Introduce new commands to support regex on popular commands RSCAN / RHSCAN / RSUBSCRIBE

or

Introduce a server level configuration filter-pattern-behavior: glob|regex to consider the pattern provided as part of SCAN / HSCAN / PSUBSCRIBE to be treated as glob or regex.

Alternatives you've considered

Use LUA scripting

Additional information

https://stackoverflow.com/questions/50373332/redis-glob-like-pattern-with-substring-excluded