Move content from SDK docs to new "Reference" docs section

### Problem

This is a proposal to create a new "References" doc section. Within that section we will move over the bulk of the content from the [SDK](https://docs.hedera.com/hedera/sdks-and-apis/sdks) and [API](https://docs.hedera.com/hedera/sdks-and-apis/rest-api) docs into these new Reference docs. For example on a page like [here](https://docs.hedera.com/hedera/sdks-and-apis/sdks/consensus-service/submit-a-message) we would move everything except the code samples into the Reference docs.

At a higher level the philosophy of the contents of the reference docs will be:
Reference docs contains propositional or theoretical knowledge that a user looks to in their work.
The only purpose of a reference guide is to describe, as succinctly as possible, and in an orderly way. Whereas the content of tutorials and how-to guides are led by needs of the user, reference material is led by the product it describes. In the case of software, reference guides describe the software itself - APIs, classes, functions and so on - and how to use them.
Source [here](https://diataxis.fr/reference/)

In contrast the SDK docs will contain guides on how to install the SDK, and guidelines on how to use the SDK functions in alignment with the reference docs. This can include code snippets and tutorials.

Feedback appreciated.

### Solution

See above.

### Alternatives

_No response_