[WIP] JAG-211 Update WMO homepage category filter

[william-buckfield]

Jira: JAG-211 Description: Currently there is a hard coded reference to filter registers on the home page based on the register category (reg:Category) being equal to http://codes.wmo.int/structure/category/WMO-I.2. Some registers incorrectly have this category assigned just so they can appear on the home page, which is not ideal

We would like to update this filter to reference registers with a reg:Category of http://codes.wmo.int/structure/category/home instead.

Tasks:

• [x] Change hard coded category reference
• [ ] Modify category tags on affected registers
• [ ] Test