Fix environment variable format for enableBMHNameBasedPreallocation

[lentzi90]

What steps did you take and what happened:

We currently use the variable enableBMHNameBasedPreallocation here.
Unfortunately, clusterctl does not pick up variables using this format (lower case), as explained here. We should change the variable to the proper format.

Unfortunately, this means a change for users. And users may already be using this variable from the clusterctl.yaml config file (where is works correctly in the current format). I'm not sure what to think about this. Does it require a minor version bump?

Edit: I think we have to change the variable, but the flag can stay the same. It would be best to do this in a minor release since it would be a breaking change for users setting the variable in clusterctl.yaml.

          args:
            - "--webhook-port=9443"
-            - "--enableBMHNameBasedPreallocation=${enableBMHNameBasedPreallocation:=false}"
+            - "--enableBMHNameBasedPreallocation=${ENABLE_BMH_NAME_BASED_PREALLOCATION:=false}"

What did you expect to happen:

The variable should be picked up by clusterctl when generating infrastructure-components.yaml. See kubernetes-sigs/cluster-api#8097 for more details.

/kind bug

[Rozzii]

/triage accepted

[metal3-io-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
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/lifecycle stale

[lentzi90]

/remove-lifecycle stale

[Rozzii]

/remove-lifecycle stale

[metal3-io-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues will close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[lentzi90]

/remove-lifecycle stale

[Rozzii]

This is something that we would like to implement but currently no-one is working on this so I am moving it to frozen.
/lifecycle frozen
/help

[metal3-io-bot]

@Rozzii:
This request has been marked as needing help from a contributor.

Please ensure the request meets the requirements listed here.

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In response to this:

This is something that we would like to implement but currently no-one is working on this so I am moving it to frozen.
/lifecycle frozen
/help

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