Gracefully handle packages breaking because of soname bumps (#1116)

Fixes #893. Changes:
* New action: "pmbootstrap pkgrel_bump"
* pmbootstrap detects missing soname depends when trying to install
  anyting, and suggests "pkgrel_bump --auto" to fix it
* Testcase test_soname_bump.py checks the pmOS binary package repo
  for soname breakage, so we see it when CI runs for new PRs
* libsamsung-ipc: bump pkgrel because of soname bump