MDL-44468 backup: use notification API

Replace a hardcoded div.notifyproblem with a API call that,
in Standard theme, outputs the same HTML.

Also removes the .notifyproblem class from the heading,
as that might cause problems for themers who expect it to be
used consistently with the API.
MDL-44468 backup: use  html_writer::div call

Simplify the renderer code with the new html_writer
div function.
MDL-45010 mod_chat: Use H3 instead of H2 in recent activity info
MDL-44619 behat: Helper to init contexts outside behat
MDL-44619 behat: filemanager field manager

Enough to allow attachments use in multi-field steps.
MDL-44619 behat: Converting MDLQA-8

In a standard forum, students can start discussions
add replies and attach files to their posts.
MDL-45046 output: reviewed standard/base layouts and converted where a better option was available
MDL-43626 survey: Addition of additional names to survey.
MDL-45036 blocks: Update to the mentee block sql to incorporate additional name fields.
MDL-44981 quiz statistics report : Differentiating '0' and no response

in numeric questions.
MDL-43673 wiki: verify page tags work as expected

This covers MDL-43109, verifying that saved tags
are available on re-edition of a page, without any warning/error.

Also official tags are verified to be working ok. With support
for multiple options added by MDL-43713 and MDL-43738.
MDL-44991 Behat: step to check if attribute does not contain text

The step checks that an attribute exists, but doesn't contain the
specified text.

Example:
Then the "class" attribute of "#mydiv" "css_element" should
not contain "accesshide"
MDL-45045 block theme: Fake blocks show empty region when editing and clicked.

Conflicts:
	lib/yui/build/moodle-core-blocks/moodle-core-blocks-min.js
MDL-43145 dock: fixed up region_completely_docked code to ignore empty regions
MDL-43145 dock: Enable regions before the drag operation starts
MDL-45012: Enable support for wma files within tinymce Moodle Media plugin
MDL-45071 mod_quiz: retrieve all the name fields when deleting a user override
MDL-45037 gradebook: Allow dashes in xml grade values to be ignored.

This was delivering an error message when trying to import an exported
xml file (from Moodle).
MDL-45049 improve debugging output in error log for NO_DEBUG_DISPLAY scripts
MDL-44270 files: handle drag-drop js error when event has null types

This can happen when the 'dragover' event fires as has been observed
in Safari. When the dataTransfer.types property of the event is null,
accessing types.length throws a JavaScript error.