[ofiwg] replacing travis CI

[Hefty, Sean]

For a while now, Travis CI has been requesting that all projects move from travis.org to travis.com.  It turns out that travis is putting credit limits on open source projects, and re-defining open source to exclude projects that have company paid employees contributing to it.  The following blog provides a nice summary:

https://daniel.haxx.se/blog/2021/06/14/bye-bye-travis-ci/

The short version is that travis no longer appears to be a viable CI option for the libfabric project.  There are some alternatives, which are being explored, including github actions and circleCI.  If anyone has any comments, please respond.

For the most part, travis CI is a subset of critical CI being run elsewhere (Intel, AWS, LANL).  The exceptions are macOS builds and Coverity.

- Sean