Release 4.0.0-rc

[ascjones]

This is the first release which may become the final 4.0.0. There may be further release candidates with breaking code
changes before the final release.

E2E Testing Framework

This release includes the first published version of the "end-to-end" (E2E) testing framework.
This enables testing of a contract by deploying and calling it on a Substrate node with pallet-contracts. See the
erc20 example for usage.

Fixed

• Add Determinism enum from pallet-contracts #1547
• Added missed WhereClosure for the generics into storage_item #1536

Changed

• FFI: no more unstable wasm import module #1522
• Fix trait message return type metadata #1531
• Bump Dylint dependencies #1551
• stabilize take_storage #1568
• make more functions be const #1574

[codecov-commenter]

Codecov Report

Merging #1590 (96a0404) into master (8ed95ea) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1590      +/-   ##
==========================================
- Coverage   71.59%   71.56%   -0.04%     
==========================================
  Files         205      205              
  Lines        6292     6292              
==========================================
- Hits         4505     4503       -2     
- Misses       1787     1789       +2     

Impacted Files	Coverage Δ
crates/allocator/src/bump.rs	88.42% <0.00%> (-1.66%)	⬇️

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[ascjones]

Converted to draft, we will wait for #1512

[ascjones]

Can open a new PR when we do the RC