Update Port schema to 2.0.0 draft spec

[sajith]

Partially addresses #102:

• Updates Port schema to include L2VPN services.
• Adds some tests.

[coveralls]

Pull Request Test Coverage Report for Build 5907160581

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 74.635%

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Totals
Change from base Build 5903842534:	0.0%
Covered Lines:	1029
Relevant Lines:	1247

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💛 - Coveralls