Remove unnecessary files

Some of them are only used by upstream, some are may have been used by us
in the past.
Whatever the reason, we don't need them anymore, so this commit removes them.
This will introduce conflicts when merging upstream but:
- Those conflicts will be easy to solve - just pick our version
- When we move to more granular way of pulling changes we will get rid of
  redundant commits from history. We could even automatically drop commits
  that only touch those files.

Author: Lorak-mmk

.gitignore

@@ -43,3 +43,14 @@ tests/unit/cython/bytesio_testhelper.c
 #iPython
 *.ipynb
 
+# Files from upstream that we don't need
+Jenkinsfile
+Jenkinsfile.bak
+appveyor.yml
+appveyor/appveyor.ps1
+appveyor/run_test.ps1
+build.yaml.bak
+docs.yaml
+doxyfile
+tox.ini
+test-datastax-requirements.txt