Refactor PSL Regular Expressions

[NassimBtk]

Use Case

Connectors use regular expressions here and there, but these are supposed to be regular expressions for the PSL grep() function, which has a very particular syntax (\| instead of just | for the logical or, e.g.).

We can't expect external users to know about PSL regular expressions, which are also very limited. We want to be able to support anything that Java regular expressions support.

Specification

Each connector will be able to specify the type of regular expressions it's using, with a top-level option in YAML:

regexType: psl # or java

Default value will be java (we're in 2024 after all).

If regexType == "psl", then we "convert" the specified regular expression to the corresponding Java regular expression. Otherwise, we leave it as is.

We will update all existing connectors to specify regexType: psl, for backward compatibility.