Docs should take a "functions first" approach

### What's Missing?

Functions are the future of Crossplane's experience and how platform engineers should be composing resources. As we move towards making Functions [GA](https://github.com/crossplane/crossplane/issues/4951), and even plan on deprecating classic patch and transform (https://github.com/crossplane/crossplane/issues/4746), we should be making them more of the "default" path when using Crossplane. New users of Crossplane should be using Functions from the very start of their Crossplane journey.

The most obvious place to update with a "functions first" approach would be the quick start guides that are still currently using classic patch and transform, e.g.:

* https://docs.crossplane.io/v1.16/getting-started/provider-aws-part-2/#create-a-custom-api

Below will track a list of broad areas that we should be updating to use and evangelize Functions more aggressively:

```[tasklist]
### Topics to update
- [ ] https://docs.crossplane.io/v1.16/getting-started/provider-aws-part-2/
- [ ] https://docs.crossplane.io/master/getting-started/provider-azure-part-2/
- [ ] https://docs.crossplane.io/master/getting-started/provider-gcp-part-2/
- [ ] https://docs.crossplane.io/master/concepts/compositions/
- [ ] https://docs.crossplane.io/master/concepts/patch-and-transform/
```