Integrate integrity hashing for WASM binary

[dkozma]

It would be good if we can verify the hash of the loaded WASM binary so that we can be sure it:

• is the one we intend to use for that version of the SDK
• hasn't been tampered with in any way

We have a couple of issues we will need to discuss regarding how to handle this:

• Right now, we use WebAssembly.compileStreaming() with a fetch request to start compiling the WASM module while it is downloading. I'm not sure if we can get any hashable data from a WebAssembly.Module (e.g. access to an ArrayBuffer of compiled data)
• If not, we may have to unfortunately only allow a URL to be passed as a wasmSrc and not accept a precompiled WebAssembly.Module. We would then probably have to drop WebAssembly.compileStreaming() in favor of doing a fetch + WebAssembly.compile in the web worker so that we can take advantage of Request.integrity.
• This will also require us to add a build process step where we get the SHA-256 of the expected WASM binary and stamp it into the SDK.

[dkozma]

@adobe export issue to Jira project CAI

[github-jira-sync-bot]

:white_check_mark: Jira issue https://jira.corp.adobe.com/browse/CAI-3358 is successfully created for this GitHub issue.