Use consistent naming for initialisms in modserver module follow-up
requested to merge gitlab-community/cluster-integration/gitlab-agent:fix-initialisms-in-modserver-module-2 into master
Improve naming for initialisms (#468 (closed)) in modserver module. This MR is a follow-up of !1252 (merged) and does not include all changes but only the following:
- Rename rpcApiKey to rpcAPIKey in modserver module
- Rename rpcApiKeyType to rpcAPIKeyType in modserver module
- Rename SentryFieldTraceId to SentryFieldTraceID in modserver module
- Rename RoutingAgentIdMetadataKey to RoutingAgentIDMetadataKey in modserver module
- Rename UnaryAgentRpcApiInterceptor to UnaryAgentRPCAPIInterceptor in modserver module
- Rename StreamAgentRpcApiInterceptor to StreamAgentRPCAPIInterceptor in modserver module
- Rename InjectAgentRpcApi to InjectAgentRPCAPI in modserver module
- Rename AgentRpcApiFromContext to AgentRPCAPIFromContext in modserver module