I've split out this issue from #9053. We need to add the following tutorials relating to ABCI++ before v0.37.0 lands:

• getting-started.md [small, 0.5 days]
• indexing-transactions.md [small, 0.5 days]
• abci-cli.md (review only) [small, 0.5 days]
• what-is-tendermint.md (ABCI section) [small, 0.5 days]
• go-built-in.md and go.md (same changes) [medium, 2 days]
• new go-abci-plus-plus tutorial to demonstrate advanced ABCI++ usage
  • for the time being, just PrepareProposal/ProcessProposal