Change Branding for root of project, major version increment

Per steering committee discussion, this pull request:

* Modifies the name of the root project from sched-assist to "sometime" in the parent pom
* Increments the major version to 2.x to avoid conflicts with sched-assist in the wild
* Designates https://github.com/Bedework/bw-sometime/issues as the new Issue Management mechanism and updates the scm

I've also added a preliminary README.

This pull request intentionally does not change the name of the sub-modules of the project. As a result, we'll still have "sched-assist-*" modules under the org.bedework.sometime groupId. We will address renaming existing modules with later efforts if there is specific need.