Allow use of heremaps with either apikey or app code and id

[alichass]

• Minimal changes to existing heremaps router
• Added new tests; seems to pass all existing tests
• Still requires documentation

Doesn't take things to 8.X, but is a quick fix for https://github.com/gis-ops/routing-py/issues/10

[nilsnolde]

Great, thanks. Will review later when I'm back on linux.

[nilsnolde]

Thanks @alichass I'll run the formatter before creating a new release