feat: EncryptionAtHost support

[andyzhangx]

Reason for Change:

This PR is actually a place holder, it's mainly for AKS to support EncryptionAtHost(Enable Encryption at Host support for VM/VMSS) (JEDI requirement) which is going to be in private preview late this month.

EncryptionAtHost functionality actually does not work by this PR since it depends on

• go sdk ready and upgrade to supported go sdk version
• EncryptionAtHost feature on public regions ready
• subs whitelist

Will make it work when the above 3 requirements are fullfilled.

Issue Fixed:

Requirements:

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

Notes:

[codecov]

Codecov Report

Merging #3041 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3041   +/-   ##
=======================================
  Coverage   70.58%   70.59%           
=======================================
  Files         145      145           
  Lines       25105    25109    +4     
=======================================
+ Hits        17721    17725    +4     
  Misses       6281     6281           
  Partials     1103     1103           

Impacted Files	Coverage Δ
pkg/api/types.go	94.05% <ø> (ø)
pkg/api/vlabs/types.go	74.31% <ø> (ø)
pkg/api/converterfromapi.go	93.82% <100.00%> (+0.02%)	⬆️
pkg/api/convertertoapi.go	93.63% <100.00%> (+0.02%)	⬆️

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[andyzhangx]

/azp run pr-e2e

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jackfrancis]

Thanks @andyzhangx, I've put a hold label on the PR. Let us know when we can consider reviewing/merging the PR.

[xuto2]

/lgtm

[jackfrancis]

/lgtm