Investigate use of `join` context for distributed sync

@justusschock is already working on this.

Since Nov 15, 2022.

## 🚀 Feature

### Motivation

Based the problems from this issue: https://github.com/Lightning-AI/metrics/issues/1297
By implementing `join` context (https://pytorch.org/tutorials/advanced/generic_join.html) for our distributed syncronization we would remove the limitation that to correctly calculate a metric the number of samples needs to be divisible by `num_gpus * batch_size` (because pytorch by default is adding additional samples to load balance).

### Pitch

Base class should derive from `Joinable` class and implement appropriate methods. It should hopefully not be too much trouble as all the sync logic is already encapsulated in a function.

### Alternatives

### Additional context