refacto: move some code into actions

(non breaking, old assignments link to new assignments)
- move lib.collapse-all into actions/collapse-all
- move lib.dir-up into actions/dir-up
- move lib.change-dir into actions/change-dir
- use setup option for change-dir global (and use the old option for
  setup)

lua/nvim-tree/actions/dir-up.lua

@@ -0,0 +1,13 @@
+local M = {}
+
+function M.fn(node)
+  if not node or node.name == ".." then
+    return require'nvim-tree.actions.change-dir'.fn('..')
+  else
+    local newdir = vim.fn.fnamemodify(require'nvim-tree.lib'.Tree.cwd, ':h')
+    require'nvim-tree.actions.change-dir'.fn(newdir)
+    return require'nvim-tree.lib'.set_index_and_redraw(node.absolute_path)
+  end
+end
+
+return M