Implement Repo field and 'Approval' process for new SALT teams to prevent spam accounts

### ISSUE
SALT (https://salt.bountysource.com/) is Bountysource's crowdfunding platform for opensource teams.

Currently, there is an increase in inappropriate & spam accounts.

To combat, we need to implement a barrier to the new team signup process. Perhaps an approval process.
https://www.bountysource.com/teams/new?salt=true


Currently, all a user/bot needs to do is complete the form and process continue.

### REQUIRED
Suggestions:
1) (At a minimum): Introduce a field in the form for Git repository link and validate

2) (Extended) Introduce an 'Approval' step that:
a) Delays team creation
b) Sends details to support@bountysource.com for manual checking of form entries & repo link for legitimacy
c) Gives Bountysource admin an option to approve --> which then creates the team account

### OPEN TO SUGGESTIONS
If you have a suggestion for how this could be achieved or an alternative solution, we are open to input, please get in touch.

### BOUNTY
A bounty will be put on this issue.
Inititally, the bounty will cover the minimum required (#1 above).
For, extended or alternative solutions, the bounty can be increased.

Start at the SALT team signup form at https://www.bountysource.com/teams/new?salt=true and trace the existing team-creation flow. Compare the minimum repository-link requirement with the extended approval proposal, including delayed creation, support notification, and admin approval; done means the selected scope is implemented and its validation and workflow are verifiable.

Written by the indexing model from the issue text.