create initial database-contents from SQL-Dump
database is now migrated on update (instead of only kept)
database adjustments to new import/export/migration process
adjustments to backup/restore for the new export/import process
print actions conducted in database_migration, post_install, pre_remove
Merge branch 'feature/database-migration' into develop
Merge branch 'develop' of github.com:beroNet/Open-PBX into develop