Improve form questions view and add option to add questions and sort form fields

[mariobehling]

1. Split form question in organiser view section “Proposal information” into two sections
a) Session Information: Title, Abstract, Description, Track, Language, Notes, Recording opt-out, Session image, Duration, Additional speakers, Availability
b) Speaker Profile, Name, Profile picture

2. Add the option to add questions same as on the “Questions” page in each area.
Ensure these "Added Questions" also show up in the respective place in the speaker's form view.
Compare to Questions area

a) These questions should show up in the speaker's form when a speaker submits a proposal for the first time.

b) These questions should show up in the respective proposal edit form and speaker's event profile after submission.

3. Also form questions cannot be sorted in different orders. Expected they should be sortable by drag and drop.

[mariobehling]

For point 1: Availability should also be moved to "Speaker Profile" area. Sorting should be 1. Profile picture, 2. Biography, 3. Availability.