Replace mock Django secret key with longer version to resolve security
warnings in development stack.
Still not production-suitable as key remains versioned in repository,
but eliminates security warnings during development workflow.
Remove dependencies on bitnami Helm charts since recent changes in
bitnami organization led to charts no longer being maintained or
published.
Enhanced the Tilt dependencies to avoid any bootstrap or refresh
errors while developping using the Tilt stack.
Making components dependant from each others increase slightly
the time required to spin up the stack the first time.
lebaudantoine