### What happened?

I'm sorry I didn't weigh in on #11277 before it was merged. I'm thinking of this specifically for how to get this properly consumed by the bindings as per #11443 

2 things to bring the grid code more in line with other endpoints.
1. Use POST if there is info to send to an endpoint instead of query string
2. Return payload needs to be nested inside a `value` key.

Current implementation of file endpoint is:
```
POST /session/:sessionId:/se/file
file: <zippedFile>
```

To minimize confusion, I think the new feature should use `files` instead of `file`:
```
POST /session/:sessionId:/se/files
{fileName: <filename>}
```
and for #11458 
```
GET /session/:sessionId:/se/files
```

### How can we reproduce the issue?

```shell
n/a
```


### Relevant log output

```shell
n/a
```


### Operating System

n/a

### Selenium version

trunk

### What are the browser(s) and version(s) where you see this issue?

n/a

### What are the browser driver(s) and version(s) where you see this issue?

n/a

### Are you using Selenium Grid?

trunk
* </tr>
 * <tr>
 * <td>GET</td>
 * <td>/se/grid/node/session/{sessionId}</td>
 * <td>Finds the {@link Session} identified by {@code sessionId} and returns the JSON-serialized
 * form.</td>
 * </tr>
 * <tr>
 * <td>DELETE</td>
 * <td>/se/grid/node/session/{sessionId}</td>
 * <td>Stops the {@link Session} identified by {@code sessionId}. It is expected that this will
 * also cause the session to removed from the
 * {@link org.openqa.selenium.grid.sessionmap.SessionMap}.</td>
 * </tr>
 * <tr>
 * <td>GET</td>
 * <td>/se/grid/node/owner/{sessionId}</td>
 * <td>Allows the node to be queried about whether or not it owns the {@link Session} identified
 * by {@code sessionId}. This returns a boolean.</td>
 * </tr>
 * <tr>
 * <td>*</td>
 * <td>/session/{sessionId}/*</td>
 * <td>The request is forwarded to the {@link Session} identified by {@code sessionId}. When the
 * Quit command is called, the {@link Session} should remove itself from the
 * {@link org.openqa.selenium.grid.sessionmap.SessionMap}.</td>
 * </tr>
 * </table>
 */
public abstract class Node implements HasReadyState, Routable {