docs: Add Solana Playground quickstart page, and add examples page for anchor contraints and types.

[ZYJLiu]

Added the following pages to Anchor docs:

• A "quickstart" page that walks through how to build, deploy, and test an Anchor program using Solana Playground
• An Anchor account constraints reference page with minimal examples (github and Solpg links)
• An Anchor account types reference page with minimal examples (github and Solpg links)

Lmk any suggestions you have to improve the examples!
(I didn't include one for rent_exempt constraint because I'm not quite sure how its used)

[vercel]

@ZYJLiu is attempting to deploy a commit to the coral-xyz Team on Vercel.

A member of the Team first needs to authorize it.

[acheroncrypto]

Lmk any suggestions you have to improve the examples!

They look great!

(I didn't include one for rent_exempt constraint because I'm not quite sure how its used)

It was added in back in Jan 2021(#17) when one could create a rent paying account. Runtime doesn't allow creating rent paying accounts anymore(solana-labs/solana#22292) but I think it was kept because there were still rent paying accounts in the network. We might remove it in the future since rent collection is being disabled(solana-labs/solana#33945).

[jacobcreech]

I think it was kept because there were still rent paying accounts in the network. We might remove it in the future since rent collection is being disabled

Just fyi, the last rent paying account ran out of funds and was garbage collected last Thursday, so it should be good to remove now

[acheroncrypto]

I think playground should support multiple Anchor versions but we can merge this PR now since most of the examples already work.

Thank you!