Synchronize the reasons in CRs status messages for different signals

[a-thaler]

Description
Currently we show following status messages at telemetry CR. We should synchronize the Reasons so that they all have similar naming patterns.

Type	Reason
MetricComponentHealthy	MetricPipelineReferencedSecretMissing
MetricComponentHealthy	MetricGatewayDeploymentNotReady.
TraceComponentHealthy	TracePipelineReferencedSecretMissing.
TraceComponentHealthy	TraceGatewayDeploymentNotReady
LogComponentHealthy	TLSCertificateExpired

See this for a full list of reasons

Criterias

• All reasons in the module CRD are using a consistent naming pattern
• CRD documentation is updated according to the changes
• Improve and review the condition messages, have it user centric and actionable. If there is more to explain, add it to the API documentation and link it.

[NHingerl]

Logs: No troubleshooting guides existing at all.

• Condition BufferFillingUp: We might need a logs troubleshooting guide for buffer overflow, similar to the troubleshooting guides for Traces and Metrics.
• Condition NoLogsDelivered: Again, probably a new troubleshooting guide required.
• Condition SomeDataDropped and AllDataDropped: Probably also a troubleshooting guide needed.

Traces + Metrics: Some troubleshooting guides exist to which we could link ("no xy arriving in the backend"), some might have to be created.