refactor: Convert misc actix-web frontend calls to async await

[Emmanuel-Melon]

Description

Convert actix-web front-end calls from Futures style into async/await style.

Testing

How should reviewers test?
This patch doesn't change any behavior and running cargo test should pass all tests.

Issue(s)

#541, #439
Closes #541.

[fzzzy]

@Emmanuel-Melon This looks good. Can you please run cargo fmt on the branch and commit and push the result.

[Emmanuel-Melon]

@Emmanuel-Melon This looks good. Can you please run cargo fmt on the branch and commit and push the result.

Just did, The CI is still failing. I'll try digging into the source of error and probably squash these commits afterwards.

It's a clippy lint warning that complains about an unnecessary let binding yet omitting it makes the result value undefined.

This error can possibly be fixed by disabling this lint.

[fzzzy]

Change the code that the lint is complaining about to this:

Ok(HttpResponse::Ok().json(meta.db.delete_storage(meta.user_id).await?))

Can you also squash this? Looking good now.

[Emmanuel-Melon]

Change the code that the lint is complaining about to this:

Ok(HttpResponse::Ok().json(meta.db.delete_storage(meta.user_id).await?))

Can you also squash this? Looking good now.

Thank you, it worked! I'll now squash and then push.