Add file_tree external pillar (should fix #13510).
Merge branch 'file_tree-for-develop' of https://github.com/imtx/salt into imtx-file_tree-for-develop
copy-edit the doc and use single quotes
Merge branch 'imtx-file_tree-for-develop' into develop
Merge pull request #15090 from thatch45/develop

Merge #15054 with fixes