[feat] add a v1alpha2 version of LinodeMachine

[eljohnson92]

What this PR does / why we need it:
This PR adds LinodeMachine to the v1alpha2 version
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:

TODOs:

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

[codecov]

Codecov Report

Attention: Patch coverage is 83.52273% with 29 lines in your changes missing coverage. Please review.

Project coverage is 67.61%. Comparing base (8746ec1) to head (f88bd46).
Report is 1 commits behind head on main.

Files	Patch %	Lines
api/v1alpha2/linodemachine_webhook.go	73.97%	17 Missing and 2 partials ⚠️
api/v1alpha1/linodemachine_conversion.go	95.45%	2 Missing and 2 partials ⚠️
api/v1alpha2/linodemachine_types.go	33.33%	4 Missing ⚠️
api/v1alpha2/linodemachine_conversion.go	0.00%	1 Missing ⚠️
controller/linodemachine_controller.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #416      +/-   ##
==========================================
+ Coverage   66.65%   67.61%   +0.96%     
==========================================
  Files          47       51       +4     
  Lines        2912     3085     +173     
==========================================
+ Hits         1941     2086     +145     
- Misses        850      874      +24     
- Partials      121      125       +4     

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