[api] Reusable api view for get_first_available_ip

[anurag-ks]

Implements and closes #33

[coveralls]

Pull Request Test Coverage Report for Build 115

• 11 of 11 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 114:	0.0%
Covered Lines:	430
Relevant Lines:	430

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💛 - Coveralls