IdStory Identity Manager

Implemented new attribute for select box component "useFirstIfOne".
Use the first searched value if exists only one and if selected value is empty. By default is attribute undefined and in that state is selected first result only if select box is required.

Commit: https://github.com/bcvsolutions/CzechIdMng/commit/ac119003f94d347b99f30bfabce21cc2b57517ae

I did test and code review.

Review notes
- Feature works on default identity contract detail, when work position is required (by form projection), awesome. But selected value cannot be cleared => selected value is returned after clear action again.
- Feature didn't work in form projection for required work position.
- Feature could work in EnumSelectBox the same way. It make sense mainly, when EnumSelectBox has dynamic options.

• I implemented disable a clear button if only one item is available and no filter (input) is used and if a select box is required.
• Empty item (no selection) is hidden too.
• I didn't implement this feature for enum component, may be in feature in new ticket.

Commit: https://github.com/bcvsolutions/CzechIdMng/commit/5f8413f1ab0c1bc021faad328d78071dc828da5d

I did test and code review, feature works in projection now and clerable button (and option) is hidden by default. Code is nice too, thx!

Note: I found just one trivial issue - when record is selected by tree modal window, then clearable button is shown again (empty option is not shown correctly). It's rare UC, so I'm closing this ticket.

Fixed problem with case, where a selectbox is rquired and user filtering items by selectbox input. If only one remains, then the selectbox select last one, but component is still unvalid.

Solution is not use this feature, if input filtering is uses.

Commit: https://github.com/bcvsolutions/CzechIdMng/commit/0976cc2279771ef08314dd8eb16c0126dbb060ba

I did test nad code review, it works and code is nice, thx!