sdk/metric: add cardinality limits as a stable feature

[pellared]

It looks like some parts of specification around cardinality limits have become stable:

• Mark cardinality limits as Stable opentelemetry-specification#4222

Probably we should look into implementing more parts of the specification e.g.

The cardinality limit for an aggregation is defined in one of three ways:
[...]
If none of the previous values are defined, the default value of 2000 SHOULD be used.

CC @open-telemetry/go-maintainers

Originally posted by @pellared in #6788

This would have to be split into several issues.