Manual Seal (#4143)

* instant/manual seal

unbounded queues are evil

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Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

add fork tests, docs, remove todos

moar docs

Update client/consensus/manual-seal/src/rpc.rs

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

remove unbound generic, parameter, docs, deps, code style changes

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Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

code style chnges

remove unused deps, remove dep renames, check if block is empty before importing, use ? for error propagation

fix tests

log errors for instant seal

use debug

code style changes, updated copyright dates

use txpool::Pool instead of BasicPool, code style changes

fixed tests

* fix tests

* requested changes from review

* check inherents len

* rebase

substrate/primitives/inherents/src/lib.rs

@@ -147,6 +147,11 @@ impl InherentData {
 			None => Ok(None)
 		}
 	}
+
+	/// Get the number of inherents in this instance
+	pub fn len(&self) -> usize {
+		self.data.len()
+	}
 }
 
 /// The result of checking inherents.