Support alternative or custom notification sounds

[chrisella]

📝 Provide a description of the new feature

The default notification sound (https://github.com/gitify-app/gitify/blob/main/assets/sounds/clearly.mp3) is quite meek and I barely notice it's even happened half the time. When coupled with the icon change being fairly small AND no native toast notifications on windows showing (at-least for me, maybe I'm setup wrong) I miss stuff all the time.

It would be nice to either have a selection of notification sounds (some more alarming than others) OR even allow a custom notification sound to be provided.

If allowing custom sounds or even multiple is more complex than desired then could we at-least expose the volume the sound is played at so it can be increased by the user from the default 0.2

https://github.com/gitify-app/gitify/blob/main/src/renderer/utils/notifications/native.ts#L99

[RuizhePang]

@setchy Can I work on this? I wanna have a try.

[afonsojramos]

Go ahead @RuizhePang! Let us know if you need any help!