Enable the Pulsar to be built using hotkeys

[Basilisk3]

Description of the proposed changes

As per the title.

Checklist

• [x] Changes are documented in the changelog for the next game version

[Garanas]

@Basilisk3 can you also look at the old build mode?

[Basilisk3]

@Basilisk3 can you also look at the old build mode?

What is the old build mode? This adds the Pulsar to the following hotkey setups:

Hotbuilding Alternative Hotbuilding Hotbuilding - Extra keys

[Garanas]

It is related to these files:

• https://github.com/FAForever/fa/blob/deploy/fafdevelop/lua/ui/game/buildmode.lua
• https://github.com/FAForever/fa/blob/deploy/fafdevelop/lua/ui/game/buildmodedata.lua