add flagd tutorial

[agardnerIT]

This PR

• Adds a demo for flagd

Notes

Try it here...

Temporarily (so you can see what this tutorial does), I've hosted it on my account (see above).

If this PR is merged, I will remove my copy in favour of this one.

[beeme1mr]

It looks great. I just left some minor feedback. It would be awesome if you could record a video of you walking through this tutorial. We could embed it here and in the flagd docs.

[agardnerIT]

Changes made but please do not merge until we have an outcome on open-feature/flagd#467

If the above linked PR is merged, I can use an OpenFeature-based repo for the code.
If it isn't I'll need to either create the example flags on the fly or use my own repo. I'd rather use OpenFeature rather than creating many copies of config so hopefully we can all agree and merge 467.

[agardnerIT]

This is ready for review. The final version:

• Uses flagd v4.4.4
• Pulls the example flags from the official flagd examples repo (not my personal repo)
• Adds a tutorial step which demonstrates the use of flagd pulling from multiple backends
• Adds links in the final step to the k8s operator killercoda tutorial + OFO docs
• Adds links to the flagd language specific providers
• Adds links to the community
• Adds Golang code sample in tutorial as a teaser for how to get started for real

When Pete's "5 minutes to feature flagging" tutorial is ready (#8) I'll add links to that too as it's a natural fit. That will happen as a different PR.