KSENROLL-14743 Create GithubStatusMojo

The GithubStatusMojo can be used to set and/or read the status on a given pull
request commit.

We will use some variant of this mojo for indicating that a build is in progress
and what the status of each build is.
KSENROLL-14743 Add GithubCommentsMojo

This mojo will be used to read and categorize comments on pull requests.

right now it just prints out what is there but later it will include the
user sign-off detection.