Merge jovonni’s dapp-orchestration-basics pr

[aj-agoric]

https://d0034bb0.documentation-7tp.pages.dev/guides/orchestration/dapp-orchestration-basics/contract/

[amessbee]

@aj-agoric can I update the title to Add docs for dapp-orchestration-basics?

I was going to create an issue but I found you already created this and it seems to me that the end goal is same. I have reviewed the above-mentioned PR but it's bit outdated now and I would start afresh while taking notes from there. WDYT.

[Jovonni]

can you list what is outdated from #1169 ? @amessbee

Why would we start from scratch, instead of just update the PR?

That would seem like extra effort

[Jovonni]

For example, this covering many single lines of the contract regarding using the API:
https://d0034bb0.documentation-7tp.pages.dev/guides/orchestration/dapp-orchestration-basics/contract/

Here is the UI in detail:
https://d0034bb0.documentation-7tp.pages.dev/guides/orchestration/dapp-orchestration-basics/ui/

and, here is the testing in detail:
https://d0034bb0.documentation-7tp.pages.dev/guides/orchestration/dapp-orchestration-basics/testing/

would help #1233 as well