Docs: update API sample response JSON to latest version

Many of the example JSON responses provided in Nomad's API documentation refer to old versions of Nomad. This results in discrepancies such as new/removed/moved fields and/or stanzas, deprecated drivers, among others. Examples of known issues are noted below some of the links, but is not intended to be exhaustive.

This list is a Work In Progress, so I encourage anyone to please add examples as they are found.

### Agent
- [ ] [Agent - Members](https://www.nomadproject.io/api-docs/agent#sample-response)
old version
- [ ] [Agent - Query Self](https://www.nomadproject.io/api-docs/agent#sample-response-2)
old version

### Nodes
- [ ] [Nodes - List Nodes](https://www.nomadproject.io/api-docs/nodes#sample-response)
old version, rkt driver, mbits

- [ ] [Nodes - Read Node](https://www.nomadproject.io/api-docs/nodes#sample-response-1)
old version, rkt driver
- [ ] [Nodes - List Node Allocation](https://www.nomadproject.io/api-docs/nodes#sample-response-2)
mbits, task group network

Review the linked Agent and Nodes API documentation sample-response sections first, comparing each example with the latest Nomad behavior. Update the listed examples to remove outdated fields, stanzas, and drivers, then verify that the response JSON matches the current API; the checklist provides the initial scope but is explicitly not exhaustive.

Written by the indexing model from the issue text.