docs: add Ory OEL to nav

[christiannwamba]

Related Issue or Design Document

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 [email protected]) 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

[christiannwamba]

@piotrmsc @aeneasr is this prominent enough? I could make it a top level item instead of a drop down item

[aeneasr]

I think it should go under products and either Ory Enterprise License or Self-Host OEL or Self-Host Enterprise License

[aeneasr]

Or alternatively - put it "Products -> Self Hosting"

And under develop:

• local development
• open source development (now called self-hosting)