Containerized development environment

[AugustHagedal]

Containerization

• Add docker file to compile and setup entry point for frontend
• Add docker file to compile and setup entry point for backend
• Add docker compose file for launching local mysql database server, backend and optional frontend for local debugging
• Add docker readme that explains using docker compose and how to access the resources
• Add optional env config, for storing local dev secrets

Backend refactoring

• Add support code-first-migration, by removing superfluous DbContexts
• Move model building to IEntityTypeConfiguration to keep DbContext clean (best practice)
• Add existing constraints to the entity configurations, to add them through code-first-migrations
• Add auto migration when program is launched through docker compose, to assure up to date schema during developement