RF: TLS checker

[vleong99]

Part of work to parallelise all tests

• Remove gock from TLS tests as it uses global scope
• Move TLS logic to checks as part of larger refactor
• Remove table tests as fields were being used as part of logic, moved logic-specific test to checks package

[codecov]

Codecov Report

Attention: Patch coverage is 58.13953% with 18 lines in your changes missing coverage. Please review.

Flag	Coverage Δ
unittests	50.77% <58.13%> (+0.23%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
handlers/tls.go	90.90% <100.00%> (+27.75%)	⬆️
checks/checks.go	0.00% <0.00%> (ø)
server/server.go	0.00% <0.00%> (ø)
checks/tls.go	58.97% <58.97%> (ø)