Add CNS IPAM check to not change state

[matmerr]

Reason for Change:

Adding an IPConfig to CNS IPAM could overwrite an existing IPConfig state. Now blocks the scenario AddIPConfig changing state from Allocated to any other state

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• [ x] adds unit tests

Notes:

[codecov]

Codecov Report

Merging #614 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #614   +/-   ##
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  Coverage   38.63%   38.63%           
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  Files          48       48           
  Lines        5371     5371           
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  Hits         2075     2075           
+ Misses       3022     3021    -1     
- Partials      274      275    +1     

[neaggarwMS]

Discussed offline with Mat, we need to move this API out from rest service as no external component (RequestController or CNI) should be able to update internal CNS state, Internally CNS will call this API on Create or update nc request for the new ipconfigs added in the update.

[neaggarwMS]

Who is going to call this API?

[neaggarwMS]

can we rename it to just CreateorUpdateNetworkContainer?

[neaggarwMS]

As discussed offline, this will require more changes to handle create and update. Lets do that change in a separate pr.