Kross doesn't want to run python scripts anymore, so Weboob plugin is dead. This patch makes it alive again.
Changes:
- no KF5::Kross dependency, as it is deprecated,
- new Python2 dependency, as it's all we need to run weboob,
- if no weboob is installed then plugin won't be compiled neither,
- renamed weboob.py to kmymoneyweboob.py and put it in kmymoney/weboob directory to avoid name clashes,
- renamed class names to better represent what they are for,
- introduced little exception handling from python scripts and informational dialogs for that,
- made single private class out of two in mapaccount, it is mystery why two of them were needed before,
- avoided crashes/never ending progress bars if no weboob backends/accounts were loaded.