Login widget

[amol-anand]

Use SUSI-light pop-up for login rather than the full page experience

There is no build process in Milo, however there are some options:

• Use microbundle locally and update the output file (e.g. https://github.com/adobecom/milo/blob/stage/package.json#L17)
• Use github actions to fetch a previously built file (e.g. https://github.com/adobecom/milo/blob/stage/.github/workflows/update-dependencies.yaml#L16)
• Manually update the file (e.g. https://github.com/adobecom/milo/commit/b344e44010c7f8c1c5d34b2d17756182edd07b78)

[amol-anand]

related to #75