feat(unstable): ability to use a local copy of jsr packages

[dsherret]

Allows specifying the directory to another package or workspace similar to patch in cargo (https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html).

// deno.json
{
  "patch": [
    "../some-package-or-workspace"
  ]
}

1. The referenced directory can be a JSR package or workspace. Referencing a single package found in a workspace will discover that entire workspace.
2. The patch field is only respected in the workspace root. Other locations cause warnings.
3. Referencing an npm package will currently warn and do nothing. Implementing this is probably two weeks of work in order to get the resolver working correctly so I removed it from this PR.

• feat: ability to patch jsr packages with local copies deno_config#100

Going to land this as unstable in order to get feedback. I'm not really sure about the name because it sounds like it will be confusing with the concept of patching dependencies in npm or patching the vendor folder.

Closes #23412
Closes #24931

[bartlomieju]

LGTM, I'm not sure about the name either, but I think we can safely land it as unstable feature for now.

[bartlomieju]

Does the message say that this patch was not used due to not matching constraints?

[bartlomieju]

Yes it does :)