Locate curl-impersonate and libcurl-impersonate in a directory which is
configurable from the command line instead of looking for them in the
current directory. '--install-dir' is passed to pytest, where a 'bin'
and 'lib' directories are expected with (lib)curl-impersonate.
Rename the Actions file for the Docker build to allow the creation of
addition Action for native builds.
The GitHub Action workflow uses a cache to speed up the Docker builds.
However, it seems that it only partially works, saving only the Docker
layers for the Firefox build. This is an attempt to solve it by using
two separate cache paths, one for each build.
Add layer caching to speed up the CI builds. In addition, optimize the
Dockerfiles by moving all the dependency installations (which are
unlikely to change much) to the initial layers.
The tests container copies files from the build containers. In order for
this to work in the GitHub actions workflow, the build images need to be
uploaded to a local Docker registry first.