Make URCPP Developer Friendly

Unable to run the app development environment in current state.

URCPP is currently not runnable using the docker container and docker-compose file with myriad of permission issues on the database and inconsistencies between the usernames and passwords being used to make the DB connection.

The repository should be modified to use a .devcontainer folder which sets up the development environment on its own.

Additional changes should address:
- Move the Dockerfile and docker-compose.yml files to a .devcontainer folder so we can develop in any environment.
- Storing the code in a volume so we don't need to rebuild every time to copy changed files into our docker image.
- Fixing permission issues between the database and the app containers. (The app currently doesn't run due to permission issues)
- Migrating to Python 3 (Scott Heggen made the migration to python 3 using local setup in [this PR](https://github.com/BCStudentSoftwareDevTeam/urcpp/pull/190)) within the docker container.

Start by reviewing the existing Dockerfile and docker-compose.yml, then compare the container setup with the Python 3 migration in PR 190. Move the container configuration into .devcontainer, provide a development volume, and verify that the app and database containers connect without permission errors and run with Python 3.

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