Contracts module rejig (#1358)

* Move prepare under code.

* Schedule update

* CodeHash

* create takes code_hash

* pass mem def and use code in vm::execute

* Actually save and load code

* Use T::Hash as CodeHash

* Explicit entrypoint name

* Return code_hash and deposit an Event

* Charge for deployed code with gas.

* ImportSatisfyCheck and FunctionImplProvider

* Progress.

* Use new infrastructure for checking imports

* Rename entrypoint to entrypoint_name

* Use strings instead of a Error enum

* Clean

* WIP

* Fix macro_define_env test.

* Fix vm code tests.

* Remove tests for now.

* Fix borked merge

* Fix build for wasm

* fmt

* Scaffolding for abstracting vm.

* Hook up execution to exec layer.

* Fix vm tests.

* Use schedule directly in WasmLoader

* Implement test language.

* Add input_data test.

* Max depth test

* ext_caller

* Simplify test.

* Add TODO

* Some tests and todos.

* top_level

* Clean.

* Restore a couple of integration tests.

* Add a few comments.

* Add ext_address runtime call.

* Deduplicate caller/self_account

* Add not_exists test.

* Change bool to TransferCause.

* Add address tests.

* Remove output_buf from parameter.

* return from start fn.

* Smart gas meter

* Tracing

* Fix prepare tests.

* Code moving

* Add ExecFeeToken

* Use tokens everywhere.

* Make it compile in no_std.

* Lift all test requirements to TestAuxiliaries

* A minor clean

* First create tests

* Remove unneeded TODO

* Docs.

* Code shuffling

* Rename create → instantiate

* Add test address.

* Code shuffling

* Add base_fee tests.

* rejig the code

* Add some comments

* on_finalise comment

* Move event deposit further

* Update Cargo.lock

* Use crates.io version of pwasm-utils

* Format todo comments

* Fix formatting

* Comments

* EmptyOutputBuf and OutputBuf split.

* Restore code_hash

* Fix node-executor.

* Fix typo

* Fix fmt

* Update srml/contract/src/account_db.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Update srml/contract/src/lib.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Line wraps

* Wrapping macros

* Add _ prefix

* Grumbles

* Doc updates.

* Update srml/contract/src/wasm/mod.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Update srml/contract/src/lib.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Add comment

* Use saturation to signal overflow

* Add prepare_test! macro

* Require deploy function.

* Add entry point tests

* Add comment.

* Rename code → code_cache to better describe

* Get rid of weird match!

* Recompile binaries

* Add comments

* refuse_instantiate_with_value_below_existential_deposit

* Little fix

* Make test more complete

* Clean

* Add integration test for instantiation

* Rebuild runtime.

* Add some tests.

* Attach an issue to a TODO

* Attach another issue

* Apply suggestions from code review

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Update srml/contract/src/exec.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Update srml/contract/src/exec.rs

Co-Authored-By: pepyakin <s.pepyakin@gmail.com>

* Recompile node_runtime

substrate/node/runtime/wasm/Cargo.lock

@@ -703,7 +703,7 @@ dependencies = [
 
 [[package]]
 name = "pwasm-utils"
-version = "0.3.1"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1093,7 +1093,7 @@ dependencies = [
  "parity-codec 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-codec-derive 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.31.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "pwasm-utils 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pwasm-utils 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 0.1.0",
  "sr-primitives 0.1.0",
@@ -1998,7 +1998,7 @@ dependencies = [
 "checksum proc-macro-hack 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2c725b36c99df7af7bf9324e9c999b9e37d92c8f8caf106d82e1d7953218d2d8"
 "checksum proc-macro-hack-impl 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2b753ad9ed99dd8efeaa7d2fb8453c8f6bc3e54b97966d35f1bc77ca6865254a"
 "checksum proc-macro2 0.4.24 (registry+https://github.com/rust-lang/crates.io-index)" = "77619697826f31a02ae974457af0b29b723e5619e113e9397b8b82c6bd253f09"
-"checksum pwasm-utils 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "efd695333cfae6e9dbe2703a6d040e252b57a6fc3b9a65c712615ac042b2e0c5"
+"checksum pwasm-utils 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e9135bed7b452e20dbb395a2d519abaf0c46d60e7ecc02daeeab447d29bada1"
 "checksum quote 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)" = "53fa22a1994bd0f9372d7a816207d8a2677ad0325b073f5c5332760f0fb62b5c"
 "checksum rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8356f47b32624fef5b3301c1be97e5944ecdd595409cc5da11d05f211db6cfbd"
 "checksum rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e464cd887e869cddcae8792a4ee31d23c7edd516700695608f5b98c67ee0131c"