Add GetParams to mirror GetOptional

[clux]

What problem are you trying to solve?

Allow querying Api::get with Any, NotOlderThan and MostRecent semantics

https://kubernetes.io/docs/reference/using-api/api-concepts/#semantics-for-get-and-list
https://pkg.go.dev/k8s.io/apimachinery/pkg/apis/meta/v1#GetOptions

Stashing this in an issue as we are waiting for #1171 first.

Describe the solution you'd like

Something similar to what was recently added to ListParams, but we cannot use the VersionMatch enum here as that is not a query parameter for get calls.

/// Common query parameters used in get calls
#[derive(Clone, Debug, Default)]
pub struct GetParams {
    /// An explicit resource version with implicit version match strategies
    ///
    /// Default unset gives the most recent
    /// "0" gives the less consistent but-cheaper "Any", and an explicit value is like `VersionMatch::NotOlderThan`.
    /// See <https://kubernetes.io/docs/reference/using-api/api-concepts/#resource-versions> for details.
    pub resource_version: Option<String>,
}

and then possibly implement some helpers to make the new semantics more easy to setup:

impl GetParams {
    pub fn at(resource_version: &str) -> Self {
        Self { resource_version: Some(resource_version.into()) } 
    }
    pub fn any() -> Self {
        Self::at("0")
    }
}

this can then be added to Request::get:

    pub fn get(&self, name: &str, gp: &GetParams) -> Result<http::Request<Vec<u8>>, Error> {
        let target = format!("{}/{}", self.url_path, name);
        let mut qp = form_urlencoded::Serializer::new(target);
        if let Some(rv) = &gp.resource_version {
            qp.append_pair("resourceVersion", rv.as_str());
        }
        let urlstr = qp.finish();
        let req = http::Request::get(urlstr);
        req.body(vec![]).map_err(Error::BuildRequest)
    }

Api interface

We already have Api::get without GetParams, and if that was the only interface it'd be easy to either add to that, or add another get variant that takes the new params. However we also have Api::get_opt and Api::entry. So not quite sure what to do about those. Don't really want to expose variant methods for all those, so it's probably better to change the signatures of these 3.

Documentation, Adoption, Migration Strategy

Release highlight if doing breaking change.

Target crate for feature

kube-core, kube-client

[nabokihms]

Honestly, thought about adding this next to list options 😅

[mateiidavid]

Thanks for a super thorough description and suggestion :) I can take this.