* Add comments and refactor Sandbox module

* Adds some comments

* Add wasmtime instance to the sandbox and delegate calls

* Adds module imports stub

* WIP state holder via *mut

* My take at the problem

* Brings back invoke and instantiate implementation details

* Removes redundant bound

* Code cleanup

* Fixes invoke closure

* Refactors FunctionExecutor to eliminate lifetime

* Wraps `FunctionExecutor::sandbox_store` in `RefCell`

* Renames `FunctionExecutor::heap` to `allocator`

* Wraps `FunctionExecutor::allocator` in `RefCell`

* Refactors FunctionExecutor to `Rc<Inner>` pattern

* Implements scoped TLS for FunctionExecutor

* Fixes wasmi instancing

* Fixes sandbox asserts

* Makes sandbox compile after wasmtime API change

* Uses Vurich/wasmtime for the Lightbeam backend

* Uses wasmtime instead of wasmi for sandbox API results

* Refactors sandbox to use one  of the execution backends at a time

* Fixes wasmtime module instantiation

* TEMP vurich branch stuff

* Adds wasmer impl stub

* Adds get global

* Fixes warnings

* Adds wasmer invoke impl

* Implements host function interface for wasmer

* Fixes wasmer instantiation result

* Adds workaround to remove debug_assert

* Fixes import object generation for wasmer

* Attempt to propagate wasmer::Store through sandbox::Store

* Wraps `sandbox::Store::memories` in `RefCell`

* Moves `sandbox::instantiate` to `sandbox::Store`

* Eliminate `RefCell<memories>`

* Implements `HostState::memory_get/set`, removes accidental `borrow_mut`

* Fixes sandbox memory handling for wasmi

* Fix memory allocation

* Resets Cargo.lock to match master

* Fixes compilation

* Refactors sandbox to use TLS for dispatch_thunk propagation to wasmer

* Pass dispatch thunk to the sandbox as a TLS

* Initialize dispatch thunk holder in `SandboxInstance`

* Comment out Wasmtime/Lightbeam sandbox backend

* Revert wasmtime back to mainstream

* Adds SandboxExecutionMethod enum for cli param

* Cleanup sandbox code

* Allow wasmi to access wasmer memory regions

* More cleanup

* Remove debug logging, replace asserts with runtime errors

* Revert "Adds SandboxExecutionMethod enum for cli param"

This reverts commit dcb2b1d3b54145ab51ad2e3fef0d980ba215b596.

* Fixes warnings

* Fixes indentation and line width

* Fix return types condition

* Puts everything related under the `wasmer-sandbox` feature flag

* Fixes warnings

* Address grumbles

* Split instantiate per backend

* More splits

* Refacmemory allocation

* Nitpicks

* Attempt to wrap wasmer memory in protoco enforcing type

* Revert renaming

* WIP wasm buffer proxy API

* Reimplement util::wasmer::MemoryRef to use buffers instead of memory slices

* Adds WasmiMemoryWrapper and MemoryTransfer trait

* Refactor naming

* Perform all memory transfers using MemoryTransfer

* Adds allocating `read`

* Adds comments

* Removes unused imports

* Removes now unused function

* Pulls Cargo.lock from origin/master

* Fix rustdoc

* Removes unused `TransferError`

* Update Cargo.lock

* Removes unused import

* cargo fmt

* Fix feature dependency graph

* Feature should flow from the top level crate
	* We should not assume a specific workspace structure
* sc-executor-wasmi does not use the feature
* sc-executor-wasmtime should not know about the feature

* Fix doc typo

* Enable wasmer-sandbox by default (for now)

It will be removed before merge. It is so that the benchbot
uses the wasmer sandbox.

* cargo run --quiet --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_contracts --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/contracts/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Revert "cargo run --quiet --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_contracts --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/contracts/src/weights.rs --template=./.maintain/frame-weight-template.hbs"

This reverts commit d713590ba45387c4204b2ad97c8bd6f6ebabda4e.

* cargo fmt

* Add ci-check to prevent wasmer sandbox build breaking

* Run tests with wasmer-sandbox enabled

* Revert "Run tests with wasmer-sandbox enabled"

This reverts commit cff63156a162f9ffdab23e7cb94a30f44e320f8a.

Co-authored-by: Sergei Shulepov <s.pepyakin@gmail.com>
Co-authored-by: Andrew Jones <ascjones@gmail.com>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>
Co-authored-by: Parity Benchmarking Bot <admin@parity.io>