Better container init

• check available templates in template server
• defaults github templates to mldock template server on github, if configured for github. No need for API key.
• resolves initialize a container from provided trainer, prediction and requirements.txt files #66 - init container from provided train, prediction and requirements files

Better development

• providing an --interactive on train/deploy which runs those commands without docker

streamlines base containers:

• migrating to a fastapi + uvicorn server
• stripping out non-base requirements (mldock logger, csv handling in request) - current containers are a cleaner basis to start from.
• splitting src/container/assets.py => src/container/lifecycle.py + src/assets.py. To help with explainability and "migratability" meaning that user altered code is not removed in a container init --container-only execution.
• brings a @Wrap decorator to provide user scripts with appropriate wrappers for error handling and startup/cleanup tasks in container lifecycle.

bugfixes:

• requirements.txt handling in container init where src/requirements.txt already existed would fail due to create=True on packagemanager.