Add .git-blame-ignore-revs file preemptively

.git-blame-ignore-revs

+# This file contains info on which commits to ignore for git blame to work
+# correctly, you can use either of these see the 'correct' blame results:
+#
+# - `git blame file.py --ignore-revs-file .git-blame-ignore-revs`
+# - `git config blame.ignoreRevsFile .git-blame-ignore-revs`
+#
+# Second option is a bit better as it'll work on the whole repo all the time