[improvement][breaking] Update templates to comply with CAPI v1.11.X

[AshleyDumaine]

What this PR does / why we need it: We need to update the templates since as-is a good number of resources are throwing API deprecation warnings. This will also help to minimize conversions as mentioned in the CAPI upgrade docs:

Note: it is technically possible for providers to keep using v1beta1 types from CAPI v1.11, but this is not recommended because it will lead to additional conversion calls.

This PR also:

• cleans up the cilium-bgp-lb flavor
• temporarily disables k3s/rke2 e2e tests and removes the k3s/rke2 flavors from the MDBook summary until both providers support CAPI v1.11.X.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer: You can read about the API changes here: https://cluster-api.sigs.k8s.io/developer/providers/migrations/v1.10-to-v1.11

TODOs:

• squashed commits
• includes documentation
• adds unit tests
• adds or updates e2e tests

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.97%. Comparing base (1307832) to head (0295320).

Additional details and impacted files

@@             Coverage Diff             @@
##           capi-v1.11     #874   +/-   ##
===========================================
  Coverage       65.97%   65.97%           
===========================================
  Files              71       71           
  Lines            7959     7959           
===========================================
  Hits             5251     5251           
  Misses           2406     2406           
  Partials          302      302           

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