[FIX] E-mail user indexing - add to conference

 * If user was registered in a conference before having an account (same e-mail), his/her identity will be automatically tied to the registration in question;
[FIX] Remove awful table width constraint
[FIX] RegForm Angular: Date field dialog

* displayFormats are now initialized
* displayFormats are shown only once when initialized
* New date field initializes dateFormat
[MIN] RegForm: removed unused regInfoMessage
[MIN] RegForm Angular: Code cleanup

* Also, removed some quick-fix TODOs
[MIN] RegForm Angular: rendering time

* Removed heavy check for any disabled filters
[FIX] RegForm Angular: binding of updated fields
[ENH] RegForm Angular: field delete confirmation
[ENH] RegForm Angular: section delete confirmation
[IMP] RegForm: Accomodation offset dates config