=UG programmes and PG Programmes links should show at all times. addresses #525
Merge pull request #562 from unikent/refactor/restrict_menu_to_ug_pg

UG programmes and PG Programmes links should show at all times.
Merge branch 'develop' of https://github.com/unikent/programmes-plant into feature/ug-pg-homepage
exclude ug/pg specific links when on the home page
add year links to home page