Create webhook for organisation invitation acceptance

[Gita Alekhya Paul]

There is no way to add an outside collaborator directly through GitHub API

• Create a Node.js webhook API
• Listen for invitation accept hooks (if existing)
• Convert all members to outside collaborators by default

[Gita Alekhya Paul]

Based on GitHub Enterprise settings, enterprise owners can set ACL to switch off cross-team visibility for organisation members. What this means:

• Members can only view public and internal repositories of the entire organisation
• They can view private repositories assigned to their team only, other team's private repositories are hidden.

This eliminates the need for a webhook to convert each member to an outside collaborator. Closing this issue on these grounds.