[REF] web, *: update bootstrap-datetimepicker to tempusdominus

* website_form, debian

Our old library for datetimepicker for bootstrap 3 is deprecated and
an updated version is developed by the same team under the new name
"tempusdominus", for bootstrap 4.

The lib is imported by taking the *unminified build* JS and the *src*
scss. Odoo is also bundling the lib better by putting the scss file
in both backend and frontend assets instead of only in common (so that
the scss is compiled differently for the frontend and the backend).

Note: the lib also needed to be patched inline to solve a bug at one
line.

Author: qsm-odoo

addons/web/static/lib/bootstrap-datetimepicker/src/js/bootstrap-datetimepicker.js

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Tempus Dominus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.