feat(types) Remove dependency to cranelift-entity

[Hywan]

Description

Don't be afraid, everything is cool.

cranelift-entity is nice, but we are limited by it. We want to go
further for some features. Those features are very likely to be
refused by Cranelift because it's out of their scope.

This patch basically copies the code from cranelift-entity inside
wasmer-types. The code has been modified to fit in our own
“no_std” strategy. The code will be modified deeper in upcoming
patches and most of the entities are likely to radically change. The
goal of this patch is strictly to not break our code while porting the
new code.

Review

• Add a short description of the the change to the CHANGELOG.md file
• Do we need to update the ATTRIBUTIONS.md file?

[Hywan]

bors try

[bors]

try

Build failed:

• Test on linux-aarch64

[Hywan]

bors try

[MarkMcCaskey]

Looks good to me.

👍 on the attributions. I'm in favor of being explicit about where the code came from and what the license is

[MarkMcCaskey]

A bit odd to see these on SecondaryMap and not on PrimaryMap but 🤷 . I find it easy to believe that these should always be inlined and that Rust probably also agrees and doesn't need to be told.

Though I think the #[inline] attributes do matter for cross-crate inlining without LTO? With LTO they don't matter, but without LTO they do. At least that's what I remember, not super confident in that memory though.

Anyways, no action needed here. Just pointing it out.

[Hywan]

Yes. That's part of the rewrite I want to do later. Let's keep the same code for the moment, and let's optimize later as planned :-). Thanks for pointing that out!

[bors]

try

Build failed:

• Test on macos-x64

[syrusakbary]

Note: on the attributions we should follow our current structure. Which is:

• No need to change ATTRIBUTIONS.md since the following is still true: wasmtime: for their API and internal documentation, as well as some internal implementations
• We need to update wasmer-types/README.md adding an Acknowledgments section with the cranelift-entity reference.

### Acknowledgments

This project borrowed some of the code for the entity structure from [cranelift-entity](https://crates.io/crates/cranelift-entity).
We decided to move it here to help on serialization/deserialization and also to ease the integration with other tools like loupe.

Please check [Wasmer ATTRIBUTIONS](https://github.com/wasmerio/wasmer/blob/master/ATTRIBUTIONS.md) to further see licenses and other attributions of the project. 

• We need the following content to the headers in the new added files:

// This file contains code from external sources.
// Attributions: https://github.com/wasmerio/wasmer/blob/master/ATTRIBUTIONS.md

[Hywan]

bors r+

[bors]

Build succeeded:

• Audit
• Code lint
• Test cross-compile on linux
• Test cross-compile on macos
• Test on linux-aarch64
• Test on linux-musl-x64
• Test on linux-x64
• Test on macos-x64
• Test on windows-x64