Rest Implementation with GET,PUT,POST,DELETE and authorization token

See merge request !127

# Conflicts:
#	extension/Source/core/Save.php

Fixes #7925. a) change CWD during split reduced to splitting only. b) fixed problem in mkDirParent() with absolute paths, c) make logger independent of CWD, d) fixed problem with `mktemp --tmpdir`(difference Ubuntu 16 / 18) by using PHP function, e) fixed some 'undefined index' problems

Refactor to use form.restMethod instead of form.permNew|edit=rest. Next step will be to eliminate formMode=FORM_REST

Fixed styling errors with too less indention. Maybe copying text between phpStrom and Sublime changed the indention.

F7904 rest api export via form

See merge request !126