Adding "follow" param for file/copy options

Also modifies the template action plugin to use this new param
when executing the file/copy modules for templating so that links
are preserved correctly.

Fixes #8998

files/copy

@@ -160,6 +160,7 @@ def main():
     force  = module.params['force']
     original_basename = module.params.get('original_basename',None)
     validate = module.params.get('validate',None)
+    follow = module.params['follow']
 
     if not os.path.exists(src):
         module.fail_json(msg="Source %s failed to transfer" % (src))
@@ -187,6 +188,8 @@ def main():
             adjust_recursive_directory_permissions(pre_existing_dir, new_directory_list, module, directory_args, changed)
 
     if os.path.exists(dest):
+        if os.path.islink(dest) and follow:
+            dest = os.path.realpath(dest)
         if not force:
             module.exit_json(msg="file already exists", src=src, dest=dest, changed=False)
         if (os.path.isdir(dest)):

files/file

@@ -125,6 +125,7 @@ def main():
     force = params['force']
     diff_peek = params['diff_peek']
     src = params['src']
+    follow = params['follow']
 
     # modify source as we later reload and pass, specially relevant when used by other modules.
     params['path'] = path = os.path.expanduser(params['path'])
@@ -177,15 +178,20 @@ def main():
             params['path'] = path = os.path.join(path, basename)
     else:
         if state in ['link','hard']:
+            if follow:
+                # use the current target of the link as the source
+                src = os.readlink(path)
+            else:
                 module.fail_json(msg='src and dest are required for creating links')
 
-    file_args = module.load_file_common_arguments(params)
-    changed = False
-
+    # make sure the target path is a directory when we're doing a recursive operation
     recurse = params['recurse']
     if recurse and state != 'directory':
         module.fail_json(path=path, msg="recurse option requires state to be 'directory'")
 
+    file_args = module.load_file_common_arguments(params)
+    changed = False
+
     if state == 'absent':
         if state != prev_state:
             if not module.check_mode: