chore: audit acceptance tests

[rakechill]

Description
Audited our acceptance testing coverage + structure

• I updated the test suite for instance types to address a duplicate test + improper syntax.
  • Context + It statements, duplicated Provisioner with KubeletConfig
• No other changes are needed to our tests since the v1beta1 migration.
• We've already added previously delayed coverage: spot instances, ephemeral disk, launch template tags.

Dug deeper into launch template provider

• I've determined that it makes sense to keep launch template provider as is, since it acts as a central place to gather dynamic + static parameters for launching instances + NICs.
• To clarify for future developers, I'll add an explanation of launch templates in the Development Guide in this repo.

How was this change tested?

• make presubmit

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

[coveralls]

Pull Request Test Coverage Report for Build 7715345261

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.626%

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Totals
Change from base Build 7704049977:	0.0%
Covered Lines:	35605
Relevant Lines:	36471

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💛 - Coveralls