Application setup scheme unified with other apps: added install_app|uninstall_app subcommands.

docker_entrypoint.sh extended by support of standard install_app, uninstall_app subcommands. Also added standardized alias --postgres-url to specify a database connection. Additionally the install_app spawns a Hivemind python code to complete its database schema setup, so potentially further spawned containers to process blocks and serve Hivemind calls have prepared environment.

Whole install_app/uninstall_app processes should have specified haf_admin role at database connection. Then sync/server processes shall use dedicated hivemind role.