* remote: move upload()/download() into tree
* remote: move path_info/path_cls into tree
* remote.azure: finish moving methods into tree
* remote.gs: finish moving methods into tree
* remote.hdfs: finish moving methods to tree
* remote.http: finish moving methods into tree
* remote.oss: finish moving methods into tree
* remote.s3: finish moving methods into tree
* remote.ssh: finish moving methods into tree
* remote.gdrive: finish moving methods into tree
* tests: update remote unit tests
* tests: update func tests
* remote: use walk_files() for all remotes
* list_cache_paths() now uses tree.walk_files() for all remotes except
local/ssh
* fix DS warnings
* bugfixes
* BaseRemote: start moving tree functions into BaseRemoteTree
* remote: add LocalRemoteTree
* remote: add cloud remote trees
* remote: move remove(), makedirs() into tree
* remote: move move(), copy(), symlink(), hardlink(), reflink() into tree
* fix attributes for moved remote methods
* tests: update unit tests for moved remote tree methods
* tests: mv unit/remote/test_remote_dir.py unit/remote/test_remote_tree.py
* fix attributes for moved remote tree functions
* tests: update func tests for moved remote tree methods
* test fixes
* fix DS warnings