Add tcpinfo v2 parser

[stephen-soltesz]

This change updates the tcpinfo parser to support standard columns for the v2 data pipeline. This change preserves the previous behavior by thinning snapshots 10:1. This change eliminates tcpinfo support for the v1 data pipeline.

This change moves structures previously defined in the tcpinfo.go file to the common schema.go, now used only by v1 datatypes. These structures include ServerInfo, ClientInfo, and ParseInfoV0.

Design:

• 2022-03 Design: tcpinfo Parser for v2 Data Pipeline

Part of:

• https://github.com/m-lab/etl/issues/1066

Testing:

• unit testing, local development mode w/ local output, and by sandbox deployment (with sandbox gardener configs, to verify processing) See: mlab-sandbox.ndt.tcpinfo.

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This change is 

[coveralls]

Pull Request Test Coverage Report for Build 7261

• 35 of 45 (77.78%) changed or added relevant lines in 4 files are covered.
• 6 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.7%) to 65.286%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
parser/ndt.go	0	2	0.0%
parser/tcpinfo.go	33	41	80.49%
<!--	Total:	35	45	77.78%	-->

Files with Coverage Reduction	New Missed Lines	%
parser/tcpinfo.go	1	77.04%
schema/schema.go	2	92.59%
active/poller.go	3	64.33%
<!--	Total:	6		-->

Totals
Change from base Build 7253:	0.7%
Covered Lines:	3972
Relevant Lines:	6084

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💛 - Coveralls