docs: add device flow documentation

[nsklikas]

Related Issue or Design Document

Adds docs for the device flow as implemented in ory/hydra#3912.

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact security@ory.sh) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

I am not sure if this is the right place to place the doc, The rest of the docs in that folder do not reference hydra configurations, but the docs in the hydra folder do not seem to document oauth2/oidc flows. Please let me know if there is a better place for it.

[vinckr]

thanks so much, this already looks great!

left a couple of comments to bring the doc in line with our docs style guide.

content wise this looks very good - I did not test it out in practice though

[vinckr]

as for the place of the doc and also place in the sidebar we can check what the best place is once its ready to merge.

@christiannwamba is currently working on a restructure of the docs, so depending on when its ready to merge we might have a different place for it.

[nsklikas]

Thanks for the review @vinckr. I think I applied all of the requested changes, please have another look when you can.

[aeneasr]

We should probably add to the oauth2 quickstart this command chain as well, to try it out quickly:

code_client=$(go run . create client \
    --endpoint http://127.0.0.1:4445 \
    --grant-type authorization_code,refresh_token,urn:ietf:params:oauth:grant-type:device_code \
    --response-type code,id_token \
    --token-endpoint-auth-method none \
    --format json \
    --scope openid --scope offline \
    --redirect-uri http://127.0.0.1:5555/callback)

code_client_id=$(echo $code_client | jq -r '.client_id')
code_client_secret=$(echo $code_client | jq -r '.client_secret')

go run . perform device-code --endpoint  http://127.0.0.1:4444  --client-id $code_client_id 

Of course not with go run . but with the ory cli prefix. We'll need to release that then first and can then merge the docs, which also kinda makes sense as we need to release this stuff in any case before merging it as it would be confusing to users/customers

[aeneasr]

Looks like there were some merge conflicts incorrectly addressed, can you please revert all non-relevant changes for this PR?

[vinckr]

this is looking great from my POV.

some "nits" that might improve readability, feel free to include or not.

[vinckr]

lgtm 🚀
thanks so much 🫶

[vinckr]

can you take another quick look please @aeneasr ? It looks fine to me now, but I want to make sure before we merge.

[zepatrik]

I think we can also merge as is and refine this later, but the current state is still pretty basic. I added some ideas for improvements.
Later we should specifically add these sections or sub-pages:

• how to get a refresh token
• concrete use-cases and recommended configuration

[unatasha8]

Added suggestions and comments

fixed

[vinckr]

lgtm, we can fix smaller issues later on if needed