Support call blocking/allowing based on configured REGEX expressions

[sranmanpreet]

This PR enhances the REGEX feature in the app.

Usecase: I receive alot of promotional calls from similar phone numbers. There is currently no way to block a specific phone number pattern, apart from blocking all unknown numbers.

Existing REGEX screen only provided option to allow incoming calls from phone numbers matching one configured pattern. With this enhancement, user can allow/block incoming calls matching any number of configured REGEX patterns.

Now REGEX screen has two input text fields, one for allowed patterns, and another for blocked patterns. Both these text fields accept comma separated REGEX patterns.

Allowed Patterns are given higher priority than Blocked Patterns, i.e. If same pattern is configured in Allowed and Blocked patterns, Silence will allow the incoming call.