Microservices part 2

[PhilipAB]

What this PR does / why we need it:
This PR implements the following microservices (and migrates the according Gargantua application logic):

• course-service
• dbconfig-service
• environment-service
• progress-service
• scenario-service
• scheduledevent-service
• session-service
• terraform-service
• vm-service
• vmclaim-service
• vmset-service
• vmtemplate-service

Milestones - General Tasks

• Implement missing resource-oriented RPCs for OTACs
• Implement missing resource-oriented RPCs for access codes
• Implement missing helper functions in access code service
• Refactor gRPC errors by introducing generic error helper functions
• Introduce general proto message definitions to prevent unneccessary code duplication
• Introduce and use a generic InstallCrds() function
• Remove legacy route from authserver and migrate into auth service
• Change proto package names and introduce convention, that these imports should always end with "pb"
• Move hflabels into an own module
• Introduce caching for the internal grpc services on list/get operations
• Introduce generic functions for the internal grpc services on list/get/delete/delete collection operations
• Add build jobs for new microservices
• Clean up unused code in gargantua main.go
• Test microservices implementation on dev deployment
• Test fresh install of hobbyfarm
• Test update of existing hobbyfarm instance
• Add PR for helm chart repository: Microservices part 2 hobbyfarm#430

Milestones - Progress of our microservices architecture (alphabetically sorted)

Course

• Implement internal course service logic
• Implement and migrate course api logic

DB Config

• Implement internal db config service logic

Environment

• Implement internal environment service logic
• Implement and migrate environment api logic

Progress

• Implement internal progress service logic
• Implement and migrate progress api logic

Scenario

• Implement internal scenario service logic
• Implement and migrate scenario api logic

Scheduled Event

• Implement internal scheduled event service logic
• Implement and migrate scheduled event api logic
• Migrate scheduled event controller logic

Session

• Implement internal session service logic
• Implement and migrate session api logic
• Migrate session controller logic

Terraform

• Implement internal terraform service logic
• Implement and migrate terraform api logic
• Migrate terraform controller logic into vm service

VM

• Implement internal vm service logic
• Implement and migrate vm api logic
• Implement vm controller logic

VM Claim

• Implement internal vm claim service logic
• Implement and migrate vm claim api logic
• Migrate vm claim controller logic

VM Set

• Implement internal vm set service logic
• Implement and migrate vm set api logic
• Migrate vm set controller logic

VM Template

• Implement internal vm template service logic
• Implement and migrate vm template api logic