fix: removing PodSecurityPolicy files from manifests folders

[allantargino]

Reason for Change:

Issue #633 describes a bug with kubelet trying to parse PodSecurityPolicy (PSP) file into a pod. The reason is because the PSP file were in a folder used by the kubelet to setup static pod definitions, causing the kubelet to try deploying it every 20s (default value for polling the definitions folder).
The current cloudinit placeholder used to inject the PSP file is MASTER_MANIFESTS_CONFIG_PLACEHOLDER. There are 2 other places in the current templates we can inject it:

• MASTER_ADDONS_CONFIG_PLACEHOLDER
• MASTER_CONTAINER_ADDONS_PLACEHOLDER
  Since addons seems more generic than container addons placeholder, I opted to move it to this location.

Issue Fixed:

fixes #633

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

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[codecov]

Codecov Report

Merging #1257 into master will increase coverage by 0.18%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master   #1257      +/-   ##
=========================================
+ Coverage   74.81%     75%   +0.18%     
=========================================
  Files         128     129       +1     
  Lines       18318   18537     +219     
=========================================
+ Hits        13705   13904     +199     
- Misses       3829    3840      +11     
- Partials      784     793       +9

[CecileRobertMichon]

lgtm

[jackfrancis]

Thanks for this @allantargino!

[jackfrancis]

/lgtm

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