Deprecate automatic unit conversion for SLIs

[j-poecher]

Currently dynatrace-service will do unit conversions for SLIs in some cases:

• when using SLI files and you specified the correct syntax as described in the documentation
• when your metric key contains builtin:service.response.time (a conversion to milliseconds is done)

Since version 1.235 Dynatrace Metrics API does support unit transformations.

So instead of relying on string prefixes and implicit conversions for certain metrics, we could deprecate these features and fully rely on Dynatrace API as it would support a lot more conversions than we do at the moment.

DOD:

• deprecate functionality and return a warning for customers
• adapt documentation
• find a migration path for existing customers

[j-poecher]

Since dynatrace-service has reached EOL on December 22nd, 2023, this issue has been closed.