Feature: Make LDAP User/Group Search Scope Configurable

[MatthewBaird-ops]

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What this PR does / why we need it:

This adds the ability to configure the User and Group search scope for LDAP based authentication.

Which issue this PR fixes

N/A

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] DCO signed
• [x] Chart Version bumped
• [x] Variables are documented in the README.md