Shuffleboard should load plugins from frc{CURRENT_YEAR}

[carbotaniuman]

Is your feature request related to a problem? Please describe.
Shuffleboard only loads plugins from user folders, which makes it impossible to install a plugin for the machine.

Describe the solution you'd like
Load shuffleboard from a shared folder, say frc2020, instead of home folders.

Describe alternatives you've considered
Installing the plugin into each user's plugin folder is ad hoc and impossible with many users on many machines.

Additional context
This is related to my gstreamer plugin, but I don't think that matters too much.