Reuse boolean for toggling the k0s endpoint reconciler

[twz123]

Description

In the controller start function, the condition to determine whether to use the k0s endpoint reconciler was written twice in very distant parts of that function. Reuse the boolean value instead. Also, rename it to a more appropriate name: There are actually two different reconcilers at play: The default one built into the API server, and k0's own implementation of it. Make it clear which implementation the boolean refers to.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Manual test
• Auto test added

Checklist:

• My code follows the style guidelines of this project
• My commit messages are signed-off
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings