Add support for Alacritty in Linux launch script

[LuisPoveda-Aerosim]

Tested running autopilot example.
Working with Unreal + Aerosim APP with Pixel Streaming

Related PR

[edufford]

I was able to test this, but even with alacritty installed, the script uses the terminal that x-terminal-emulator points to as a higher priority so it still used gnome-terminal at first.

To switch x-terminal-emulator to point to alacritty, I had to do the following since installing alacritty via the cargo install alacritty process doesn't register it as an alternative default:

which alacritty
(was installed to /home/ed/.cargo/bin/alacritty)

sudo update-alternatives --install /usr/bin/x-terminal-emulator x-terminal-emulator /home/ed/.cargo/bin/alacritty 50
sudo update-alternatives --config x-terminal-emulator

After switching x-terminal-emulator to alacritty, this worked for me. I think leaving the behavior of prioritizing x-terminal-emulator is fine, so it's up to the user to have alacritty installed and registered to be the new default like listed above if they want the launch scripts to use it.

[edufford]

@praveen-palanisamy This looks good to go for me, but the related PR on the Unreal project side needs a minor change to fix the title text before merging these.