* removed `.ci/dev/unit/Jenkinsfile` and
`.ci/dev/integration/Jenkinsfile` - they don't seem to be used anywhere
* switched mandatory tests to linear build - modeled after Corda
Enterprise
* switched nightly regression tests to linear build - modeled after
Corda Enterprise
* Update to Jackson 2.9.8 to address multiple security issues, and update warning note about
updates to clarify that it refers to 2.10+. When the note was added 2.9.7 as the highest
available version in the 2.9.x series.
* Add PR code checks Jenkinsfile