IdStory Identity Manager

This is not a frontend issue - the false value for Boolean is represented as null in IcAttribute. I have to find the right place to fix it.

I have made a change on the backend where the empty Boolean value is now translated to false. On the frontend, I had to change the basic null checking to comparison with undefined.

This seems to work well during testing. I tested it with a virtual system and a PostgreSQL table. There are some caveats:

1. this will not work retroactively but only for new provisionings
2. for a virtual system, the attribute type has to be Boolean - both in the schema and in the form definition. This one I'm worried about because it will not be backward compatible. By default, you can now add a new attribute to a virtual system and only set it as Boolean in the schema, let it be Text in the form definition and everything will work fine. This will change because it will fail now. After an upgrade, those who added their custom attributes for virtual systems and set them to type Boolean will see failures in provisioning and will need to manually change the attribute type in the form definition. I don't see any way that we can prevent that. The one good news is that this will not be a problem for the ENABLE attribute.

We will discuss it before a review.

PR: https://github.com/bcvsolutions/CzechIdMng/pull/218

@kucerar, can you give me feedback please?

LGTM, works nicely.

Changelog is updated to.