Add feature to (a) regenerate the form/wizard slug and (b) allow user entered value for form/wizard slug

[barseghyanartur]

• Allow regeneration of the form/wizard slug.
• Allow user entered value for form/wizard slug.

In the form edit interface, on a separate tab (next to the properties), have a tab named "Slug".

There should be two separate forms there.

• One with single slug field and a button - for changing the slug to whatever user wants it to be. All checks are assumed to be present.
• Another form would contain a single button only. Clicking the button should regenerate the slug from the current title.