new: generic blank snippet to render a map in meta-tags

See tests for expectations.
new: generate HTML meta fields for view name, page type and user type

This allows the JS to take actions depending on the correct context.
new: retrieve AJAX error detail from HTML error page in the response

Currently we cannot request the server with a JSON response to the AJAX
form submissions because when the request is successfull, the server
always sends the redirected HTML page, and jQuery fails parsing it as a
JSON.

Now, if the JSON response is not available, we try to find the error
detail in the header subtitle of the complete HTML error page in the
response.

Note that if we change to JSON, the JSON response will be automatically
parsed.
new: $$.util.meta JS to retrieve view name, page type and user type
fix: include commit message (aka comment) in parsed module metadata
refactor: enable 'read-only' option for all parameters
fix: correct module forms before submission
change: format commit date in module history page
fix: display form field for image link (aka logoLink) correctly
fix: AJAX request URL for save form in user page (edit and new modes)
refactor: $$.util.meta.{isView() -> isViewName()}
fix: don't ask for commit message when saving user (edit or new modes)
fix: add base href to ../ for HTML templates static display

Note: since we moved the templates to a dedicated folder in b21f7cd,
the CSS and JS references for the static files have to be prefixed
with ../ to enable correct static display.
new: allow skipping save confirmation and commit message with ALT key