refactor(test): consistent package structure for tests

[maggieneterval]

Reorganizes package parse_hal:

• Splits each hal_to_{service} method into its own file.
• Splits each hal_to_{service} tests into corresponding file, in parse_hal_test package within parse_hal directory.
• Potentially controversially, moves "end to end" tests that read from YAML into each hal_to_{service}_test file as well, since they are in fact testing the conversion of a hal config to a service config (just from YAML rather than Go structs).
• Moves test YAML into testdata file as this directory name seems to be a Go convention (it is ignored when you run go build).

[ezimanyi]

🧹 💅 📦 🏗️ 💯

[ezimanyi]

@Mergifyio refresh

[mergify]

Command refresh: success