datasette publish option for installing extra apt-get packages

[simonw]

I ran into a need for this while playing with https://github.com/simonw/datasette-ripgrep - I need to install the ripgrep Ubuntu package when I deploy the plugin using Cloud Run.

[simonw]

Design:

datasette publish cloudrun blah.db --apt-get-install ripgrep --install datasette-ripgrep

[simonw]

Already have a pattern for extra packages in the form of the --spatialite feature:

datasette/datasette/utils/__init__.py

Lines 50 to 55 in f2e2bfc

	SPATIALITE_DOCKERFILE_EXTRAS = r"""
	RUN apt-get update && \
	apt-get install -y python3-dev gcc libsqlite3-mod-spatialite && \
	rm -rf /var/lib/apt/lists/*
	ENV SQLITE_EXTENSIONS /usr/lib/x86_64-linux-gnu/mod_spatialite.so
	"""