Docs-V1 (UserGuide): Add /managing-application root files

[eeshaanSA]

What this PR does:

Add root files for userguide/managingApplication/*

Please check v0.55x docs for comparision

Why we need it:

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 29.29%. Comparing base (c32694e) to head (eb95cc2).
⚠️ Report is 21 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6345      +/-   ##
==========================================
+ Coverage   28.82%   29.29%   +0.46%     
==========================================
  Files         560       21     -539     
  Lines       59937     1758   -58179     
==========================================
- Hits        17277      515   -16762     
+ Misses      41339     1197   -40142     
+ Partials     1321       46    -1275     

Flag	Coverage Δ
.	?
.-pkg-app-pipedv1-plugin-analysis	?
.-pkg-app-pipedv1-plugin-kubernetes	?
.-pkg-app-pipedv1-plugin-kubernetes_multicluster	?
.-pkg-app-pipedv1-plugin-scriptrun	54.83% <ø> (ø)
.-pkg-app-pipedv1-plugin-terraform	38.65% <ø> (ø)
.-pkg-app-pipedv1-plugin-wait	?
.-pkg-app-pipedv1-plugin-waitapproval	?
.-pkg-plugin-sdk	?
.-tool-actions-gh-release	19.23% <ø> (ø)
.-tool-actions-plan-preview	?
.-tool-codegen-protoc-gen-auth	0.00% <ø> (ø)

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[khanhtc1202]

@eeshaanSA Can you help resolve the conflict?

[eeshaanSA]

breaking this PR into separate files, so they are easier to review, should be done by end of month!