Allow handling special verbs/resources

[clux]

There's a couple of special resources that need to be handled in less generic ways. E.g. just on pods alone:

pods/attach
pods/portforward
pods/eviction
pods/exec
pods/log

and maybe some node specific stuff. Don't see drain + cordon in the openapi.
We could allow customising these, but maybe the list is short enough to just have it as a feature.

[clux]

We can make a generic_action query (with a verb and noun param) on RawApi and make native object specific wrappers on them in Api.

We do have do do some basic native object mapping of types to enum names anyway, so may as well map generic actions to those types.

At least, this is the cleanest way of doing it, I've thought of so far. Happy to take PRs for it. Don't have an immediate need for it myself yet.

[clux]

We have a decent pattern for this that doesn't require massive amounts of generics:

1. Implement subresource queries straight on RawApi without restrictions (for now):

impl RawApi {
    /// Get a pod logs
    pub fn log(&self, name: &str, lp: &LogParams) -> Result<http::Request<Vec<u8>>> {
        ...
    }
}

2. Make a marker trait for the subresource:

pub trait LoggingObject {}

impl<K> Api<K>
where
    K: Clone + DeserializeOwned + KubeObject + LoggingObject,
{
    pub async fn log(&self, name: &str, lp: &LogParams) -> Result<String> {
        let req = self.api.log(name, lp)?;
        Ok(self.client.request_text(req).await?)
    }

    pub async fn log_stream(&self, name: &str, lp: &LogParams) -> Result<impl Stream<Item = Result<Bytes>>> {
        let req = self.api.log(name, lp)?;
        Ok(self.client.request_text_stream(req).await?)
    }
}

3. Designate what resources implement this subresource:

impl LoggingObject for Object<PodSpec, PodStatus> {}
impl LoggingObject for Object<PodSpec, Void> {}

That ought to be it. Write one test case in examples (e.g. examples/log_openapi.rs).

Ought to be simple PRs for people who need extra functionality for subresources!

[clux]

Opened #127 to replace this.