[FWE] Deprecate redundant tutorials

[ericwindmill]

We should remove 'learn by doing' resources that are made redundant by the new getting started.

1. src/content/tutorials/server/get-started.md
   This page is almost entirely redundant now. Covers installing the SDK, creating a console app, and running it. All of this is covered in greater detail and with more modern context in get-started/hello-world.md.

2. src/content/tutorials/server/fetch-data.md
   This page is also almost entirely redundant now, and all the concepts are fully covered in get-started/http.md and get-started/data-and-json.md.

3. src/content/tutorials/server/cmdline.md
   This one is a bit more debatable. The difference is that it teaches 'raw' APIs for I/O and building CLIs, where the new Get Started is a little more high-level. That said, raw APIs don't really need "learn by doing" tutorials.

[ericwindmill]

@parlough @antfitch @connie-ooi WDYT?