Change user facilitator crud flow

[maebeale]

• This work Closes New ProjectUsers aren't properly saving via Facilitator Form #452

What is the goal of this PR and why is this important?

• Better allow missing Facilitator or User
• Only store name and avatar on Facilitator (unless no facilitator...)
• Only store email on User (unless no user...)
• Change crud flows to follow suit with the above
• Add links on crud views between the two
• Fix the issue w nested project_users on Facilitator form
• Change project_users section to only be editable by admins
• Surface more profile display preference booleans
• Add two 'sections' to Facilitator show (Authored content, Contributed content)

How did you approach the change?

• Add missing decorators, and add/move main_image_url methods to decorators
• Change default showing of 'Spotlighted Facilitator' badge on Facilitator profile so it's based on assn and not always showing
• Update title_with_badges signature to accept font_size and show_hidden_badge (instead of admin, since it's more descriptive)
• Add new facilitator_profile_button helper for use on indexes etc
• Change facilitator name method to no longer reference associated user
• Introduce facilitators/show_card partial, and add bookmarks to models that needed it for the partial to work
• Add display methods to workshop_log so it'll display nicely on Facilitator show

Anything else to add?