gps feeder fixes and improvements

[int0x27]

Fixed several issues in gps2val: NOTE: command line arguments are broken, to be addressed in another PR.

• Slightly reduced size of the image (apk cahce removed)
• Workaround for a sighandler deadlock in gpsd_feeder, preventing image from stopping: thread.join(1) + os._exit(1)
• Disabled SIGQUIT handler in order to force an app crash in case sighandler hangs in the future
• Added some extra dumps for config
• Dockerfile uses entrypoint.sh script to allow custom cmdline arguments to gpsd_feeder.py NOTE: gpsd is started as background job and it has dumps now, entrypoint.sh makes sure gpsd is terminated after python exits. Also the image has a hardcoded config file, so command line args are overriden by it.

Also fixes and improvements in workflow file (e.g. make it git clone friendly):

• Improved github context checks to guess if we should have rights to push on ghcr.io
• Now should be able to run on forked repos (without self-hosted arm64 runner).
• In forked builds, just linux/amd64 platform is built as qemu build for arm64 needs ~3h to finish.
• Added nice summary for ephemeral ttl.sh images / ghcr.io tags in workflow summary

Signed-off-by: Ivan Kirchev Ivan.Kirchev@bosch.com

[SebastianSchildt]

I tried making the resulting image smaller, the Dockerfile was quite sloppy anyway.

Does not solve the root cause for the 413 (probably this https://github.com/containerd/containerd/pull/7459 ) but maybe solves our problem while making the container image better as well. Fingers crossed