Cleanup and adjustments according to discussions

[samumantha]

• Registration page (https://aaltoscicomp.github.io/NoBSC/registration/) -> moved to other pages
• about page: missing soc RSE info under "supported by"
• Call for sessions now has likely different formats than the submission form?
• Clearer info on submission, voting and remove mention on "make it somewhat available"
• cool things and problems: where is that in schedule? -> moved to scicomp meetup
• clearer unconference text
• request a session: limit to one space (reg form)
• when to attend: remove "(or earlier)" from rse-fi, we start at 11 with lunch.
• Remove Session request -> similar to unconference and unclear if we have time to organize