Add clones and pushes to audit logging (BB-9452)

We would like to add clones and pushes activities to the audit logging as it would help us to keep track of:

1. The active users
2. The owner of the content being pushed to Bitbucket (especially when it does not match with the "committer")
3. After maintenance such as BFG and LFS, who did clone the latest version of the repository.

These changes would be related to the feature http://blog.bitbucket.org/2013/08/15/new-audit-logs-give-you-the-who-what-when-and-where/