Relates to
https://linear.app/sourcegraph/issue/REL-81/service-definition-otel-collector but does not close it.

Some of the StandardConfig features (notably PodTemplateConfig) assume that there is only one pod template "thing" per service. The otel service contains an agent daemonset and a collector deployment, which have quite different characteristics. We're less likely to paint ourselves into a corner if we split these services at the config level.

testdata refactoring was done using:

find internal/appliance/reconciler/testdata/sg -name '*.yaml'  | xargs sed -Ei 's/openTelemetry:/openTelemetryAgent:/g'
find internal/appliance/reconciler/testdata/sg -name '*.yaml'  | xargs sed -Ei '/openTelemetryAgent:/i\  openTelemetryCollector:\n    disabled: true\n'
go test ./internal/appliance/reconciler -args appliance-update-golden-files

Test plan

Golden tests included. No behavioural changes are shown.

Changelog