Add failover connector to the contrib distribution

[douglascamata]

The failsafe connector already exists in alpha state for all signals and even mentions in its README that it should be in both the contrib and k8s distributions. I'm not sure whether it truly needs to be in the k8s distribution, but I'm very certain it should be at least in the contrib one.

Correctly built with the ocb tool.

Fixes #701.

[ChrsMark]

Since the component mentions k8s distro as well, shouldn't that be added for k8s as well?

Pinging @fatsheep9146 and @akats7 as code-owners of the component.

[douglascamata]

@ChrsMark I'm not sure whether it should be there, that's why I didn't add it yet. I thought that maybe the README could be mentioning those two distributions because the contents were copied from a different component's README. 🤷

But if we all agree the failover connector should also be in the k8s distribution, I'm happy to swiftly add it there.

[povilasv]

I think k8s distro already has it https://github.com/open-telemetry/opentelemetry-collector-releases/blob/main/distributions/otelcol-k8s/manifest.yaml#L76 so only contrib is missing it? :)

[mx-psi]

Can we add a changelog note?

[douglascamata]

@mx-psi done. Thank you!