In particular for editing sticky blocks. If the admin addes one at site level,
then the teacher should not be able to change its configuration from
the course page, but should be able to set the position on this page.
This mostly works now, but ...
* The UI needs further work. In particular we need a non-advanced mode.
* This only works for blocks that use a new edit_form.php to replace config_instance.html.
* .. and so far I have only implemented edit_form.php for the HTML block so far.
* Needs to be enabled (with no block-specific config) for blocks without instance config, so you can control their positioning.
tjhunt