Allow setting the default number of replicas for controlplane components

[alvaroaleman]

What this PR does / why we need it:

Allows setting the default number of replicas for controlplane components. Defaults the number of apiserver replicas to two, as requested by the sebastian.

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:

Documentation:

Does this PR introduce a user-facing change?:

[BREAKING] The default number of apiserver replicas was increased to 2. You can revert to the old behavior by setting `.Kubermatic.apiserverDefaultReplicas` in the `values.yaml`

[alvaroaleman]

/assign @nikhita

[nikhita]

/lgtm
/approve

Lgtm on the what the PR does, but out of curiosity:

Defaults the number of apiserver replicas to two, as requested by the sebastian.

Why are we doing this?

[kubermatic-bot]

LGTM label has been added.

Git tree hash: aa85d3f6ca971a419479a12eb7adbca22ba9d3fa

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nikhita

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• OWNERS [nikhita]
• api/cmd/OWNERS [nikhita]
• api/pkg/controller/OWNERS [nikhita]

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[nikhita]

Ooops requires rebase 🤦‍♀️

[alvaroaleman]

Why are we doing this?

Because that makes the api much more ha. For the controllers it doesn't matter as much, as they are not doing anything without the leader lock anyways

[nikhita]

/lgtm

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 13ee1902702bcb1e07e359c12cfa706deae64731

[alvaroaleman]

Also, a downtime of the API is something ppl notice instantly as kubectl doesn't work anymore, downtime of the controller-manager or scheduler just results in parts of the reconciling not happening instantly anymore