Language Strings for Navbar

[Jeremy Hopkins]

There are some issues with lang strings in the navbar:

1) Inconsistency, some use strings in adaptable others use core. All should be within the theme for consistency / flexibility

2) "People" (under this course) is hard coded and cannot be changed via lang customisation / translation.

[Info 3bits]

People is already removed from renderers.php and added to the strings.