Refine the OSX computer set up instructions

[chrisjonesBSU]

We need to go through and double check that the instructions for setting up an OSX computer are up to do. I recently had to update my macbook to Big Sur, and I've been able to get everything running (including the vmd gsd-plugin), so I'll work on this.

[jennyfothergill]

it seems there are duplicates as well wiki/Setting_Up_an_Account_on_a_Mac_Labtop.md and wiki/Setting_up_an_OSX_Computer.md

[miaklop]

Seems like the wiki/Setting_Up_an_Account_on_a_Mac_Labtop.md has virtually nothing in it. I vote we delete it

[miaklop]

Reference #27 for problems with the OSX instructions