Release RC5

[JoshOrndorff]

This PR updates the recipes to Substrate v2.0.0-rc5. Because the Substrate Service had a major refactor introduced in RC5, and the Recipes are the largest collection of non-runtime examples, this is a significant update. In addition to updating all code and corresponding writeups, this PR also begins the process of scoping down the recipes by pruning recipes that show outdated patterns, and combining multiple recipes together to reduce overall maintenance. There is still plenty more of that work to be done, but this is a start.

Mandatory TODO:

• [x] Do I need Dummy FPRB in babe grandpa node?
• [x] Update PoW node
• [x] Update manual seal node
• [x] Update RPC node
• [x] Remove clippy linting suppression (cherry pick from #332)
• [x] Revise writeups
• [x] Fix test mocks

Optional TODOs:

• [ ] Update to newer version of Substrate Fixed
• [x] prune execution-schedule recipe
• [x] combine manual seal and rpc nodes into one (less maintenance)

[JoshOrndorff]

I'm currently stuck getting the manual seal node to build. The issue is a generic type mismatch in the ServiceParams struct.

To reproduce the error run cargo check -p manual-seal. The error is:

error[E0308]: mismatched types
  --> nodes/manual-seal/src/service.rs:98:3
   |
98 |         params, select_chain, inherent_data_providers, commands_stream,
   |         ^^^^^^ expected `()`, found struct `jsonrpc_core::io::IoHandler`
   |
   = note: expected struct `sc_service::builder::ServiceParams<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u32, sp_runtime::traits::BlakeTwo256>, sp_runtime::OpaqueExtrinsic>, _, _, _, (), _>`
              found struct `sc_service::builder::ServiceParams<_, _, _, _, jsonrpc_core::io::IoHandler<sc_rpc::metadata::Metadata>, _>`