show a user friendly description of the starting unit template

closes #6209
beautify starting unit notification when joining server

move LobbySettingsNotification into it's own ServerTrait
Merge pull request #6217 from Mailaender/starting-units-classname

Fixed lobby start unit notifications not showing class names
Introduces ReloadModifier
and renames ROF -> ReloadDelay
ReloadModifier & ROF -> ReloadDelay yaml changes
Upgrade rule for ROF > ReloadDelay renaming.
Adds length display support for PCM & IMA music.
Merge pull request #6089 from reaperrr/wavlength

Add WavSoundLength to show track length in music player
Merge pull request #6079 from reaperrr/rof-modifier

Adds ReloadDelay modifier & renames ROF to ReloadDelay
Fixes year numbers in license text in file headers.
Merge pull request #6296 from mizipzor/fix-license

Fixes year numbers in license text in file headers.
Added a trait that removes an actor when prereqs are met, with delay.
Merge pull request #6109 from WolfGaming/RemoveOnPrereq

Added a trait that removes an actor when prereqs are met, with delay.