META: Create Contribution Events community initiative pages

Problem/Motivation

This community project would be well served by having a supporting community initiative. Community initiatives provide wider visibility.

Steps to reproduce

Proposed resolution

Add a community initiative page to the Community initiatives section of drupal.org.

Remaining tasks

1. Figure out what to include on the pages (Bug Smash Initiative is a great example)
2. Create the community initiative pages (see child issues)
3. Update the project page to point to the main community initiative page

User interface changes

API changes

Data model changes