[web] allow configuration of the Content-disposition value
The `set_content_type` function now takes and optional `disposition` parameter
to control the value of this HTTP header.
Use of `Content-disposition: inline` with a filename parameter are valid, so
the presence of filename does not allows to choose between `attachment` and
`inline`
if 'same_as' in schema:
sync_schema_props_perms('same_as', syncperms=False)
sync_schema_props_perms('Bookmark', syncperms=False)