core: do not delete/insert edges when changing the order via mod_menu

(cherry picked from commit f82a7d3d406e25f4a4b1bcbfb24caea6242b4040)
core: remove nested transaction from the z_edge_log_server check.

(cherry picked from commit f00bd2061baffe26ee407ea19fe73fbc39a53a31)
mod_admin: if date is not editable, display it as text.

(cherry picked from commit 591aa487a7fdef7da2a3f3f0823e12378bc8f486)

Conflicts:
	modules/mod_admin/templates/_edit_date.tpl
mod_admin: more generic css for .category spans.

(cherry picked from commit 08e2642eade710f4a007f5ab6a5cdefc4078575f)

Conflicts:
	modules/mod_admin/lib/css/zotonic-admin.css
mod_menu/mod_admin_frontend: enable editing of collections as side-menu.

(cherry picked from commit 5a0fbaf4d4f727a18f6a3d720165838a18c5b437)

Conflicts:
	modules/mod_admin_frontend/templates/_admin_frontend_edit.tpl