contracts: Add seal_rent_status (#8780)

* Move public functions up in rent.rs

* Added RentStatus

* Fix test name for consistency

Co-authored-by: Michael Müller <michi@parity.io>

* Mark rent functions as unstable

* Add unstable interfaces to README

* Fix doc typos

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Use DefaultNoBound

* Simplify calc_share(1)

* Don't output empty debug messages

* Make `seal_debug_message` unstable

Co-authored-by: Michael Müller <michi@parity.io>
Co-authored-by: Andrew Jones <ascjones@gmail.com>

substrate/frame/contracts/src/benchmarking/code.rs

@@ -103,6 +103,7 @@ impl ImportedMemory {
 }
 
 pub struct ImportedFunction {
+	pub module: &'static str,
 	pub name: &'static str,
 	pub params: Vec<ValueType>,
 	pub return_type: Option<ValueType>,
@@ -171,7 +172,7 @@ where
 				.build_sig();
 			let sig = contract.push_signature(sig);
 			contract = contract.import()
-				.module("seal0")
+				.module(func.module)
 				.field(func.name)
 				.with_external(parity_wasm::elements::External::Function(sig))
 				.build();
@@ -292,6 +293,7 @@ where
 		ModuleDefinition {
 			memory: Some(ImportedMemory::max::<T>()),
 			imported_functions: vec![ImportedFunction {
+				module: "seal0",
 				name: getter_name,
 				params: vec![ValueType::I32, ValueType::I32],
 				return_type: None,
@@ -321,6 +323,7 @@ where
 		ModuleDefinition {
 			memory: Some(ImportedMemory::max::<T>()),
 			imported_functions: vec![ImportedFunction {
+				module: "seal0",
 				name,
 				params: vec![ValueType::I32, ValueType::I32, ValueType::I32],
 				return_type: None,