[Feature request] import/no-same-package-import

Refactoring some code today in a package called 'our-utils' I noticed one of the files in that package was importing like:

```js
import { someDep } from 'our-utils';
```

Now in reality, `someDep` was in a file adjacent to the one we were working in, and the optimal import would be, in my view:

```js
import { someDep } from '.';
```

Is there any rule already that does this? I don't think so, but maybe I overlooked one. This would be like the `import/no-self-import` rule, but working on entire packages rather than single files.

Start with the existing import/no-self-import rule mentioned in the issue and inspect how it determines the current import target. Define the package-level behavior for imports like `our-utils`, add coverage for the adjacent-module example, and confirm the new rule reports only the intended cases.

Written by the indexing model from the issue text.