refactor: REST Catalog implementation (apache#965)

Followup of apache#962

apache#962 Introduced a bug where it is not some of the methods allow for both
`StatusCode::OK` and `StatusCode::NO_CONTENT` as success cases, when in
reality it should be one or the other (this was me, sorry about that).

This PR attempts to unify the 3 different types of response helpers that
essentially all do the exact same thing slightly differently. The main
addition here is a function `query_catalog`:

```rust
    // Queries the Iceberg REST catalog with the given `Request` and a provided handler.
    pub async fn query_catalog<R, H, Fut>(&self, mut request: Request, handler: H) -> Result<R>
    where
        R: DeserializeOwned,
        H: FnOnce(Response) -> Fut,
        Fut: Future<Output = Result<R>>,
    {
        self.authenticate(&mut request).await?;

        let response = self.client.execute(request).await?;

        handler(response).await
    }
```

By allowing each `Catalog` method to specify how they want to handle the
responses, it gets much finer control on the success/error cases as well
as the error messages. Previously, there were 3 functions that all did
similar things:

```rust
    pub async fn query<R: DeserializeOwned, E: DeserializeOwned + Into<Error>>(
        &self,
        mut request: Request,
    ) -> Result<R> {

    pub async fn execute<E: DeserializeOwned + Into<Error>>(
        &self,
        mut request: Request,
    ) -> Result<()> {

    pub async fn do_execute<R, E: DeserializeOwned + Into<Error>>(
        &self,
        mut request: Request,
        handler: impl FnOnce(&Response) -> Option<R>,
    ) -> Result<R> {
```

I'm also somewhat using this as a chance to refactor some other parts of
this crate, mainly documentation and examples.

@Xuanwo It would be great if I could get feedback on some of these
proposed changes before I keep going!

Author: connortsui20