Finally get rid of AppCatalogModel mockup class.

Use murano-api calls for all AppCatalog needs.

Change-Id: Ibc50d492a1ced84a52ebb0a25d7ad7cf9655af2c
Fix checkbox appearance in ModifyPackageForm.

And remove more obsolete code.

Partially implements: blueprint service-defitions-migrate-to-apps-ui

Change-Id: I94f40c3c53def47329118935ed0f5d2674daa0cb