Impove Onboarding / Membership management process

[sseerrggii]

Some improvements on Register - Membership management:

• Review register process (create account and confirm email), some users get stuck in this process
• Remember users without membership (15 days after register) they should ask for membership in some Organization or the user will be deleted when user have 1 month on the platform without membersehip
• Super admin (active admin) allow to filter users without membership (we will manually manage this list and remove old users without membership)
• Fix duplicate applications Duplicate applications #763
• Force page https://www.timeoverflow.org/organizations to users logged in without membership (some users don't know what to do if they see pages like https://www.timeoverflow.org/pages/about)
• Improve text of email notifications new membership application, specify the name of the organization user want to join
• Notify orgs admins (CCO) when membership remove their membership
• On https://www.timeoverflow.org/organizations Organizations list place BdTOnline (org 402) always at the begining (it's the TimeBank that you can join if you don't find any in your location)