[craft jobs] use target from .craft.ini

~~Therefore force existence of .craft.ini

I only tested it for the Appimage job~~

To make this possible drop the --target option.

Also use the new blueprint related srcDir option instead of the now deprecated global --src-dir (see packaging/craft!163 (merged))

This is to replace !128 (closed) (see discussion there for details)

The .craft.ini file would need to look like this if you want to overwrite the target

[BlueprintSettings]

kde/kdemultimedia/kdenlive.version = master