Update addon list to remove STB

[Boomer-1]

Sensible toolbox has long since abandoned, and last worked in 1.18 It's time to remove it from the list.

[svr333]

What if we just have a no longer maintained section underneath the actual list and put it there?

STB was definitely a well liked addon and imo its better to keep a reference to it than to fade it to the past.

[Boomer-1]

we could, but if that's the case all the old ones that were removed should be put there