Remove channels/profile#dit

Since we have users#edit this is not necessary anymore
Import channels_subscriber policy from catarse
Refactor channels_subscriber policy spec
Migrate channels_subscribers controller to pundit
Remove channels from cancan
Remove all channel's ability
Create project faq policy
Migrate projects/faqs to pundit
Remove project faq from cancan
Create authorization policy
Migrate authorizations controller to pundit
Remove authorizations from ability
Refactor channel subscriber policy spec messages
Merge pull request #162 from neighborly/jl-pundit-authorization

Migrate Authorization to Pundit
Refactor project faq policy spec messages
Merge pull request #160 from neighborly/jl-pundit-project-faq

Migrate Project Faqs to Pundit
Merge pull request #158 from neighborly/jl-pundit-channels

Migrate Channels to Pundit
Import contribution policy from catarse
Refactor contribution policy
Remove payment_service_fee_paid_by_user from permited params in contribution policy