Add setBasePath util function to allow changing icon import path

[spwoodcock]

Problem

• I am using the UI on a frontend behind a proxy, under the path /mapnow on the server.

• I can load the JS without issues, but loading the icons I need in my app fails, as it looks for them under the normal path:
  http://MY_DOMAIN:7050/shoelace/assets/icons/map.svg
  when it should be looking under
  http://MY_DOMAIN:7050/mapnow/shoelace/assets/icons/map.svg

  My dir structure:

  

• Shoelace already provides a util function to handle this use case: https://shoelace.style/getting-started/installation#setting-the-base-path

• However, because we are re-exporting shoelace, using this function as it is will not work.

Solution

• Re-export the util function from shoelace, so we can use it like this:

  import { setBasePath } from '@hotosm/ui/dist/components';
  setBasePath('/mapnow');