PWX-36817/PWX-32899_pt1: K8s DNS domain fix

[zoxpx]

What this PR does / why we need it:

The px-operator should not assume the K8s cluster is running a default domain .svc.cluster.local

FIX:

• as a fix, we will use portworx-api.<namespace> hostname
• this relies on /etc/resolv.conf to supply search <domain> statements

Which issue(s) this PR fixes (optional)
Closes # PWX-32899 (part 1)

Also PWX-36817 (<< dedicated ticket)

Special notes for your reviewer:

Tested manually on a K8s cluster with modified DNS domain -- Px still deploys correctly, and no significant errors observed in operator's log.

Note also that the plugin @.../component/plugin.go still uses the .svc.cluster.local default DNS domain

• this DNS-domain was not changed, since plugin works on OCP, and OCP does not offer modification of DNS-domain as a part of the install process

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (92c4cd6) 75.85% compared to head (26c9e4c) 75.85%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1437   +/-   ##
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  Coverage   75.85%   75.85%           
=======================================
  Files          66       66           
  Lines       19017    19017           
=======================================
  Hits        14426    14426           
  Misses       3563     3563           
  Partials     1028     1028           

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[zoxpx]

Thanks for the review Piyush --

• merging this PR as it's not requiring other changes (i.e. no vendor-dependencies)
• currently not cherry-picking to any older releases

[zoxpx]

Requested cherry-pick to operator-24.1.0 branch