feat: allow volunteers to register themselves

[thatfiredev]

PLEASE DO NOT MERGE

Although the flow is working minimally, there are still a few minor corrections to be made:

• [x] ~VolunteerAssets and VolunteerCategories that have been soft deleted are still showing;~ We're now using hard deletes as a workaround.
• [x] Step 1 of the registration does ~not~ show the user name if they have already registered;
• [x] Step 2 of the registration does ~not~ show the selected assets and categories if user has already registered;
• [x] ~Some navbar features might need to be changed~ created a second layout without a navbar. This layout is used after a user has logged in

~Note to self: Allow Organizations login in a separate PR~