Debugging an OS update

[vipulgupta2048]

Add steps to debug an OS update or at least have a section on where customers can find logs.

Context: https://balena.zulipchat.com/#narrow/stream/346010-channel.2Fsupport-operations/topic/Gathering.20support.20data/near/421415222

[vipulgupta2048]

Update the following link: https://docs.balena.io/reference/OS/updates/self-service/#running-an-update in the process of completing this.