Bug 27336: Sanitize correctly HTML id

Bug 27336: Sanitize correctly HTML id

Valid characters are alphanumeric characters (a-zA-Z0-9), hyphen (-)
and underscore (_)

https://www.w3.org/TR/CSS21/syndata.html#value-def-identifier

All invalid characters will be replaced by '_'

Test plan:
1. Go to Administration » System preferences and click on 'Searching'
   tab
2. You should see a console error (Uncaught Error: Syntax error,
   unrecognized expression: #collapse_Did_you_mean/spell_checking)
3. Apply patch
4. Make sure the error is gone
5. prove t/Koha_Template_Plugin_HtmlId.t

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>