Allow app-level push API keys

Changed

• Allow the use of app-level push API keys. When an app-level push API key is used, the resource attributes for the name and environment should not be specified. These resource attributes are now optional, although the use of one requires the other.

• Make most resource attributes optional. Allow for the resource attributes pertaining the revision, the hostname, the language integration and the application path to not be present. This allows the AppSignal collector to more easily ingest data from arbitrary OpenTelemetry sources.

  Note that usage of these resource attributes is still recommended. Traces sent without these attributes may be tagged with the wrong hostname or revision, or have their error backtraces parsed incorrectly.

This release can be installed through our collector packages and Docker image.