Adding Port.type attribute according to Topology 2.0 spec

[italovalcy]

Fix #139

Heads-up: this PR will sits on top of PR #138

Description of the change

• Adding Port.type attribute on the Port object and PortHandler
• Adding unit tests
• Adding port_v2.json testing data model file

[coveralls]

Pull Request Test Coverage Report for Build 10324364059

Details

• 7 of 8 (87.5%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.05%) to 80.514%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/sdx_datamodel/models/port.py	6	7	85.71%
<!--	Total:	7	8	87.5%	-->

Totals
Change from base Build 10324344975:	0.05%
Covered Lines:	1347
Relevant Lines:	1654

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💛 - Coveralls