NULLED XF2 ADD-ON AIXF Resource Tag Line on View 2.3.7

Compatible XF 2.x versions: 2.3
Additional requirements XenForo 2.3.7
XenForo Resource Manager 2.3

Purpose:
Shows the XFRM resource Tag line (subtitle) directly on the resource's item page (under the title).

## What it does
- Adds a tiny template modification to public:xfrm_resource_view that prints `{$resource.tag_line