fix(manager): disable metrics server from controller runtime

[akhilerm]

Signed-off-by: Akhil Mohan akhil.mohan@mayadata.io

Why is this PR required? What issue does it fix?:
NDM was crashing on systems were port 8080 is already in use. NDM daemonset uses the host network and if the port 8080 on host machine is being used, NDM crashed. This was because controller-runtime by default tries to start a server at port 8080 as part of initialization, and if it fails, the initialization errors out.

What this PR does?:
Disables the default metrics server in daemonset and operator.

Does this PR require any upgrade changes?:
No

If the changes in this PR are manually verified, list down the scenarios covered::
Run the NDM daemonset on a machine were port 8080 was already in use and no crashes were observed.

Any additional information for your reviewer? :
Mention if this PR is part of any design or a continuation of previous PRs

Checklist:

• Fixes #
• PR Title follows the convention of <type>(<scope>): <subject>
• Has the change log section been updated?
• Commit has unit tests
• Commit has integration tests
• (Optional) Are upgrade changes included in this PR? If not, mention the issue/PR to track:
• (Optional) If documentation changes are required, which issue on https://github.com/openebs/openebs-docs is used to track them:

[codecov-commenter]

Codecov Report

Merging #473 into master will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master     #473   +/-   ##
=======================================
  Coverage   40.53%   40.53%           
=======================================
  Files          71       71           
  Lines        3488     3488           
=======================================
  Hits         1414     1414           
  Misses       1966     1966           
  Partials      108      108           

Impacted Files	Coverage Δ
cmd/ndm_daemonset/controller/controller.go	19.14% <0.00%> (ø)

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