fix(transforms): var conflicts in cjs-to-esm require-to-import transform

[js07]

When name of imported module is same as name of variable in scope, it causes a conflict. This PR fixes that by renaming the imported module to ${pckgName}Module, if it's a default import.

For example:

• Input:

  require("foo-bar")(5);
  const fooBar = "hello world";
  console.log(fooBar);

• Output before ❌:

  import fooBar from "foo-bar";
  fooBar(5);
  const fooBar = "hello world";
  console.log(fooBar);

• Output after ✅:

  import fooBarModule from "foo-bar";
  fooBarModule(5);
  const fooBar = "hello world";
  console.log(fooBar);

When the imported module is a named import, it's renamed to ${pckgName}${importedName}.

For example:

• Input:

  const bar = "hello world";
  require("foo").bar(5);
  console.log(bar);

• Output before ❌:

  import { bar } from "foo";
  const bar = "hello world";
  bar(5);
  console.log(bar);

• Output after ✅:

  import { bar as fooBar } from "foo";
  const bar = "hello world";
  fooBar(5);
  console.log(bar);

Part of #50