Histogram support in runtime metrics (#6935)

* Histogram support in runtime metrics

Add support for histograms to the runtime metrics. Additionally add
`polkadot_parachain_verify_dispute_signature` histogram which tracks the
time needed from the runtime to verify a single validator signature of a
dispute statement.

* Add noops

* u64 instead of f64

* Update buckets

* Wrap `get_current_time()` in runtime metrics

* Change the dimension of the Histogram from usec to sec

* Fix a compilation error

* Update buckets

* Fix `on_signature_check_complete` calculation

* Update buckets

* Update buckets

* formatting

* Another weights update

* Adjust buckets again

* Final buckets adjustment

* Revert "Fix a compilation error"

This reverts commit 06290b40a39eeb78de2602d8916a39edf7a8b714.

* Update primitives/src/v4/metrics.rs

Co-authored-by: Andrei Sandu <[email protected]>

* Use `saturating_sub` for time difference calculation

* Pass nanoseconds to client instead of seconds (using f64 in runtime is dangerous)

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Co-authored-by: Andrei Sandu <[email protected]>