Docs: Add documentation for hosting Kratos on a sub domain

[JoblersTune]

There are specific configurations considerations and requirements when hosting Kratos on a subdomain. Need to figure out all these details and document them to make this flow easier for anyone attempting this in the future.

Might be related to #2949

[JoblersTune]

Some initial considerations:

• see https://www.ory.sh/docs/kratos/reference/configuration

Within the Kratos configuration file it might be necessary to set the domain property on cookies and sessions for session handling and CSRF cookies.

[mkurapov]

@JoblersTune do you think we should provide an ory kratos config file in the docs for this?

[JoblersTune]

Ideally yes. But this kind of got bumped down the priority list since @tadejgolobic moved away from that approach so we haven't researched extensively or resolved the issue yet,. I.e more work than just docs still.

I think a line in the docs saying "if you host it on a sub domain read kratos docs" is sufficient for now unless it becomes a bigger priority.

[mkurapov]

if you host it on a sub domain read kratos docs" is sufficient for now unless it becomes a bigger priority.

Makes sense, in the meantime, should we just provide a config file similar to testnet's current deployment to show a working solution? We don't need to mention sub domains.

[brad-dow]

@JoblersTune @mkurapov
Currently, our docs contain this brief aside and a link to the Kratos docs. Should I put this issue back in the user docs backlog or are we at a point where we can build onto this?

[JoblersTune]

I think that's up to the Rafiki team. It was a priority when we were using it that way ourselves for Rafiki Money but we pivoted approaches. Personally I wouldn't make this a priority unless someone asked about it. But I also don't think it's my call any more.

@mkurapov perhaps you can provide an answer for @brad-dow.