SecurityContext part 1: applying PodTemplate for InitContainers

[vlibov]

Tracking issue

Related to #5462

Why are the changes needed?

The Issue #5462 describes the problem in detail.

What changes were proposed in this pull request?

1. Apply the PodTemplate settings to the InitContainers. In particular, this allows the SecurityContext settings to be applied also to the InitContainer.

How was this patch tested?

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Splits the original PR #5556 into two smaller PRs

Docs link

[codecov]

Codecov Report

Attention: Patch coverage is 15.38462% with 11 lines in your changes missing coverage. Please review.

Project coverage is 36.16%. Comparing base (bed761c) to head (59d9e58).
Report is 1 commits behind head on master.

Files	Patch %	Lines
...ns/go/tasks/pluginmachinery/flytek8s/pod_helper.go	15.38%	10 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5664      +/-   ##
==========================================
- Coverage   36.17%   36.16%   -0.01%     
==========================================
  Files        1302     1302              
  Lines      109492   109505      +13     
==========================================
- Hits        39606    39602       -4     
- Misses      65748    65764      +16     
- Partials     4138     4139       +1     

Flag	Coverage Δ
unittests-datacatalog	51.37% <ø> (ø)
unittests-flyteadmin	55.29% <ø> (-0.04%)	⬇️
unittests-flytecopilot	12.17% <ø> (ø)
unittests-flytectl	62.28% <ø> (ø)
unittests-flyteidl	7.08% <ø> (ø)
unittests-flyteplugins	53.28% <15.38%> (-0.04%)	⬇️
unittests-flytepropeller	41.74% <ø> (ø)
unittests-flytestdlib	55.35% <ø> (ø)

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[eapolinario]

This looks reasonable. Can you add a few unit tests to https://github.com/flyteorg/flyte/blob/master/flyteplugins/go/tasks/pluginmachinery/flytek8s/pod_helper_test.go?