Add SHARK user guide to root of docs directory (archived)

[amd-chrissosa]

Progress on #458

This PR adds a SHARK user guide to root of docs directory and does some basic information re-architecture to point installation paths of current main readmes to the new user guide.

This PR is still a WIP (testing it) but focus is:

• One new landing page and removal of duplicate installation paths in SD folder to point to both nightly / new release page depending on use case.
• Incorporated a mini guide on supported options for the SD Server / Client in the user guide.
• Changed root readme to include a path for users so that anyone who lands on the main SHARK readme can quickly get started as a non-developer.

[ScottTodd]

I'd personally put this at /docs/user-guide.md, but I could also see a case for /docs/users/README.md or where you have it now at docs/README.md.

Organizing into docs/users/ and docs/developers/ gives us a nice way to direct users away from guides that are less actively maintained.

[amd-chrissosa]

Let's do an incremental step. I'll go with user-guide.md since that accomplishes the goal and is to understand. We can further restructure later as we get more developer-only and user-only content.

[ScottTodd]

"Python environment" isn't very specific. Maybe suggest venv?

Suggested change

	You will need a recent version of Python. We recommend also setting up a Python environment.
	You will need a recent version of Python. We recommend also setting up a [Python virtual environment](https://docs.python.org/3/library/venv.html).

[amd-chrissosa]

Cleaning up language

[ScottTodd]

Hah. Python.

pyenv and Python venv are two different things. They can work together though.

https://github.com/pyenv/pyenv

If you use pyenv, you can get behavior like this:

python --version
# 3.10

pyenv install 3.11
pyenv global 3.11
python --version
# 3.11

Then when you create a venv:

python -m venv .venv
source .venv/bin/activate
python --version
# 3.11

Without venv pyenv (edit: ugh, now I'm confusing myself), you would have the code you have here:

python --version
# 3.10
python -m venv .venv
source .venv/bin/activate
python --version
# 3.10
deactivate

python3.11 -m venv 3.11.venv
source 3.11.venv/bin/activate
python --version
# 3.11

So pyenv lets you just call python as if it was python3.11, but venv is what actually isolates installed packages into a virtual environment

[ScottTodd]

This can be simplified now

Suggested change

	pip install transformers
	pip install dataclasses-json
	pip install pillow
	pip install shark-ai
	pip install shark-ai[apps]

[ScottTodd]

Let's put some context here (and/or in https://github.com/nod-ai/SHARK-Platform/blob/main/shortfin/python/shortfin_apps/sd/README.md) about what "SD" is.

• Link to https://stablediffusionxl.com/
• The page at https://huggingface.co/stabilityai/stable-diffusion-xl-base-1.0 has a good overview:

  Model Description: This is a model that can be used to generate and modify images based on text prompts.

The guide here should have enough information so users know what the server will do: text prompt(s) in, images out

Once we have official support for more models, we'll want to structure the user guide so there is a branch: general setup -> choose your model/app. Fine to start with the SDXL focus though.

[ScottTodd]

Oh, and general tip for sending PRs on GitHub: use a branch other than main on your fork. Putting commits directly on main can be error prone since you can accidentally push to the upstream remote instead of your fork. If you have multiple branches active at a time, which one is main and which isn't?

[amd-chrissosa]

Deprecating this PR in favor of: #528. Second commit has all relevant changes.