fix: refactor connect by config to identify localhost

[sweatybridge]

What kind of change does this PR introduce?

Bug fix #1588 (comment)

What is the new behavior?

• fixes migration up --linked not connecting to remote
• fixes inspect <...> --local not connecting to local
• fixes db pull --local not connecting to local
• fixes localhost check for migration squash

Additional context

Add any other context or screenshots.

[coveralls]

Pull Request Test Coverage Report for Build 6650292980

• 23 of 48 (47.92%) changed or added relevant lines in 30 files are covered.
• 8 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.05%) to 58.595%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/migration.go	0	1	0.0%
internal/db/diff/migra.go	2	3	66.67%
internal/inspect/bloat/bloat.go	0	1	0.0%
internal/inspect/blocking/blocking.go	0	1	0.0%
internal/inspect/cache/cache.go	0	1	0.0%
internal/inspect/calls/calls.go	0	1	0.0%
internal/inspect/index_sizes/index_sizes.go	0	1	0.0%
internal/inspect/index_usage/index_usage.go	0	1	0.0%
internal/inspect/locks/locks.go	0	1	0.0%
internal/inspect/long_running_queries/long_running_queries.go	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
internal/migration/list/list.go	3	94.49%
internal/gen/keys/keys.go	5	12.31%

Totals
Change from base Build 6650160053:	-0.05%
Covered Lines:	5665
Relevant Lines:	9668

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💛 - Coveralls