Update docs and finalize for 0.72.0

[clux]

Plan on releasing 0.72.0 tomorrow (with or without the outstanding docs thing).

Stuff to put in highlights:
(NB: TODOs blocked by release on docs.rs)

Ergonomics improvements

A new runtime::WatchSteamExt (#899 + #906) allows for simpler setups for streams from watcher or reflector.

- let stream = utils::try_flatten_applied(StreamBackoff::new(watcher(api, lp), b));
+ let stream = watcher(api, lp).backoff(b).applied_objects();

The util::try_flatten_* helpers have been marked as deprecated since they are not used in the new pipeline.

A new reflector:store() fn allows simpler reflector setups #907:

- let store = reflector::store::Writer::<Node>::default();
- let reader = store.as_reader();
+ let (reader, writer) = reflector::store();

Additional conveniences getters/settes to ResourceExt for manged_fields and creation_timestamp #888 + #898, plus a GroupVersion::with_kind path to a GVK, and a TryFrom<TypeMeta> for GroupVersionKind in #896.

CRD Version Selection

Managing multiple version in CustomResourceDefinitions can be pretty complicated, but we now have helpers and docs on how to tackle it.

A new function kube::core::crd::merge_crds (TODO: docs.rs link) have been added (in #889) to help push crd schemas generated by kube-derived crds with different #[kube(version)] properties. TODO: link to kube-derive segment.

A new example showcases how one can manage two or more versions of a crd and what the expected truncation outcomes are when moving between versions.

Examples

Examples now have moved to tracing for its logging, respects RUST_LOG, and namespace selection via the kubeconfig context. There is also a larger kubectl example showcasing kubectl apply -f yaml https://github.com/kube-rs/kube-rs/blob/7715cabd4d1976493e6b8949471f283df927a79e/examples/kubectl.rs#L149-L170 as well as kubectl {edit,delete,get,watch} via #885 + #897.

[clux]

Will merge and take the highlights from here as the release in a few hours.