The explicit install was added earlier due to a broken zlib
package (see issue #1517). This has now been fixed for a while in
alpine and can be removed.
Must drop wkhtmltopdf because it is not available anymore in alpine.
Weasyprint is supposed to be a drop-in replacement, doing poorer
outputs in my eyes. There are alternatives like downloading
pre-compiled binaries, but not for all platforms.
zlib 1.2.12-r0 is not working with openjdk, it affects the checksum
calculation of the db migrations. It must be at least 1.2.12-r1. For
some reason joex has this newer version, but the restserver image not.
They are installed explicitely now on both images.
That's why the migration is now disabled on rest-server in the
docker-compose file. It is ok if this is run on one server. It can now
happen that on first start joex is migrating the db and the restserver
tries to do things that don't work yet - it is a corner case. This is
removed with the next version.
Refs: #1517
Since this file cannot be changed inside the image, and people need to
specify a new file or env variables, it doesn't make sense to add it.
Also if it is present, it is preferred to the env variables.
