ci: Expand parallel matrix with build modes

.gitlab-ci.yml:
Expand the parallel matrix with build modes per profile.
Do not run netboot with the baseline profile, as codesigning is not supported yet (#132).
Remove tagging for fast-single-thread and secure, as archiso builds will only ever be used for testing the project. This
also ensures not introducing memory pressure on a single build machine.
6 jobs for issues/131 in 60 minutes and 25 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Lint
passed #22249
shellcheck

00:00:21

 
  Build
passed #22250
build: [baseline, bootstrap]

00:30:04

passed #22251
build: [baseline, iso]

00:36:50

passed #22252
build: [releng, bootstrap]

00:11:26

failed #22253
build: [releng, iso]

01:00:02

passed #22254
build: [releng, netboot]

00:31:56

 
Name Stage Failure
failed
build: [releng, iso] Build The script exceeded the maximum execution time set for the job
[mkarchiso] INFO: Done! systemd-boot set up for UEFI booting successfully.
[mkarchiso] INFO: Preparing an /EFI directory for the ISO 9660 file system...
[mkarchiso] INFO: Done!
[mkarchiso] INFO: Cleaning up in pacstrap location...
[mkarchiso] INFO: Done!
[mkarchiso] INFO: Creating SquashFS image, this may take some time...
Parallel mksquashfs: Using 32 processors
Creating 4.0 filesystem on /mnt/scratch-disk/tmp/tmp.T0S3SJNXau/releng/iso/arch/x86_64/airootfs.sfs, block size 1048576.
ERROR: Job failed: execution took longer than 1h0m0s seconds