Remove Cluster and Machine Controller

[xmudrii]

What this PR does / why we need it:

This PR removes Cluster and Machine Controllers in preparation for migrating to CRDs.

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 part of #83

Special notes for your reviewer:

Once this is merged, provider on the master branch will not be usable. Instead, users have to use releases until #126 isn't merged, which should be very soon considering the biggest part is already done.

Release note:

NONE

[xmudrii]

/hold until #123 and #124 are not merged

[xmudrii]

/hold

[xmudrii]

This PR is ready to be merged.

Once this is merged, provider on the master branch will not be usable. Instead, users have to use releases until #126 isn't merged, which should be very soon considering the biggest part is already done.

Note that it's required for this PR to be merged before #126 can be merged.

/hold cancel
/assign @nikhita @alvaroaleman

[nikhita]

/lgtm
/approve

/hold
Feel free to unhold at your discretion :)

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nikhita, xmudrii

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• OWNERS [nikhita,xmudrii]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[xmudrii]

Let the party begin 🎈
At this point, until #126 is not merged, master is going to be broken
/hold cancel