[WIP] Upgrade regex plugin to accept multiple matches

[jmcook1186]

What
Upgrade the existing regex plugin so that it can accept multiple matches

Why
Our current regex plugin only supports single matches, which limits it to simple use cases. Expanding it to support multiple matches will make it more flexible and able to handle more complex applications.

Context
Requested by Green-Software-Foundation/if-plugins#85

Prerequisites/resources
none

SoW (scope of work)

• update regex plugin source code
• documentation updated
• test cases added

Acceptance criteria

tbc

Given (Setup): Describes the initial state of the system or the preconditions for a change.

When (Action): Describes the specific action or behavior that is being tested/changed.

Then (Assertion): Defines the expected outcome or behavior of the system after the action in the "When" step is performed.