CI config and git export tweaks

Add paths-ignore filters for GHA PRs
Stop .tools/ and .gitattributes commits from triggering CI
Exclude CI files from git exports

.appveyor/epics-base-7.yml

@@ -38,6 +38,8 @@ skip_commits:
     - 'documentation/*'
     - 'startup/*'
     - '.github/*'
+    - '.tools/*'
+    - '.gitattributes'
     - '**/*.html'
     - '**/*.md'