Draft: (Don't Merge) Install H3 extension

[rustprooflabs]

Details

This adds the h3 extension into the Docker image. As it stands, I do not plan to merge this into main. To install h3 via pgxn I needed a version of cmake newer than what is on Debian 11. Building a newer cmake from source is a huge slowdown to initial docker build.

I haven't tried going down the path of building the h3 extension from source. I suspect I will encounter the same minimum cmake version.

real	19m7.325s
user	0m2.124s
sys	0m1.271s

[rustprooflabs]

Increases the raw sizes reported by docker images, from 1.73 GB to 2.23 GB (+29%)

rustprooflabs/pgosm-flex            h3         fca216bb86ac   14 minutes ago   2.23GB
rustprooflabs/pgosm-flex            0.10.2     70fa27f0b1bb   3 weeks ago      1.73GB

Increases the compressed size quite a bit, from 531.55 MB to 666.8 MB. (+25%)

[jacopofar]

Out of curiosity, why not Debian 12?

[rustprooflabs]

@jacopofar Because the base image postgis/postgis:16-3.4 uses Debian 11. I didn't want H3 in here strongly enough (yet) to go through the headache of rewriting the Dockerfile. Partly because I figured it'd naturally get there before too much time goes by, and the rest because I don't like fighting Docker 😄

I would be willing to consider a PR changing the base Dockerfile to support this. If we go down that route I'd prefer Ubuntu over Debian just because I use it more and it's easier to manage packages.

Curious back at ya -- Is there a use case you'd like to see supported with H3 baked into this image?

[jacopofar]

No not really, I just got a notification about this PR and was curious :)

I had a similar problem with old tzdata in Debian (docker-library/postgres#1046) used as a base image for Postgres. I'm not using H3 though so no idea about this use case