FieldSets names shouldn't be used

[vbradnitski]

Depending on application startup order same fieldsets may get different names. Name is given when schema XML is parsed via simple static increment.

[vbradnitski]

FieldSet is just a group of inputs and it's name not reflected both in path of data and form, but guillotine uses name in schemas config.

[rymsha]

FieldSet used to have name but now it is history. Now name should not be used. We need to make it more apparent in code: switch to null or random