Updated the build script to check if the `import` line for a file is
referencing the editor scripts base package, and when there is a match
the `import` statement will be changed from:

```js
from "@phaserjs/editor-scripts-base.js";
```

to

```js
from "../../phaserjs_editor_scripts_base/index.js";
```

This fix has a few limitations:

* if any other npm packages are added to this library, this change will
not fix those
* the generated `phaserjs_editor_scripts_quick` needs to be placed
at the root of the phaser editor project, next to the original location
of the `phaserjs_editor_scripts_base` folder.

Signed-off-by: Scott Westover <scottwestover2006@gmail.com>

Re-ran the `build-browser.js` script so files use the updated import
path for the `@phaserjs/editor-scripts-base.js` npm package reference.

Signed-off-by: Scott Westover <scottwestover2006@gmail.com>

Updated the build script for the generated browser folder

updated readme to include a note about the placement of the generated browser folder for vanilla js projects.

Signed-off-by: Scott Westover <scottwestover2006@gmail.com>

updated readme

[GH-1] update build script for browser folder to use a relative import statement for script base folder