Move project stage filter to checkboxes

The /projects browser currently shows "Stages" as a 4th tab within the same UI used to filter projects by tags for topics/tech/events:

Remove this 4th tab and instead list out all the stages as checkbox options ABOVE the tags widget, with all of them presented in order with descriptions like they are in the project edit form::

In the filter sidebar they will have checkboxes instead of radio buttons though, and all of them will be checked by default except for `Hibernating`

Use an input name like `stages[]` for the check boxes as this will produce in PHP an array of all the checked values that can be applied to `$conditions` in the `handleBrowseRequest` method for projects