CLOUD-869 Enhance Jenkinsfile to skip builds for specified non-trigger files (#977)

* Enhance Jenkinsfile to skip builds for specified non-trigger files

* Add support for manual builds.

* remove .e2eignore from .e2eignore

* Add .github directory to .e2eignore

* invert the logic and make it a early return(moving to top), reducing nested ifs

* Refactor Jenkinsfile to remove unnecessary leading './' from file paths

Author: ptankov

.e2eignore

@@ -0,0 +1,10 @@
+.github/**
+docs/**
+examples/**
+licenses/**
+code-of-conduct.md
+CONTRIBUTING.md
+LICENSE.md
+README.md
+.gitignore
+release_versions