Create a generalised rule-builder component

What does this MR do and why?

Blocked by #96678

This MR partially solves #321882 (closed)

By extracting common parts for rule builders into base component.

Describe in detail what your merge request does and why.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

No visual changes

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Enable feature flag

   Feature.enable(:scan_execution_rule_mode)

2. Go to URL/root/PROJECT_ID/-/security/policies
3. Create new policy
4. Select Scan execution policy and click Add rule

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #321882 (closed)