MachinePool support

[anmazzotti]

kind/feature

What this PR does / why we need it:

This PR adds support for MachinePool, plus some refactoring.

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 #569

Special notes for your reviewer:

Checklist:

• squashed commits into logical changes
• includes documentation
• adds unit tests
• adds or updates e2e tests

[alexander-demicev]

thanks!

[furkatgofurov7]

@anmazzotti thanks for the PR. Can we also document how to enable and use this feature with example(s) in the book?

[anmazzotti]

@furkatgofurov7 it is enabled by default.
Also none of the flags is documented right now, so not really sure what to do.
Do you want me to document them all? Shall this be a dedicated page?

Additionally, most of the flags are not configurable even by the end user, so that needs to be sanitized first in the *-components.yaml file

FYI: #588

[furkatgofurov7]

Do you want me to document them all? Shall this be a dedicated page?

Additionally, most of the flags are not configurable even by the end user, so that needs to be sanitized first in the *-components.yaml file

FYI: #588

I was thinking we could start documenting MP specific flag and extend the doc later as needed for other flags in the future