[Identity] Move to use static web assets support.

[javiercn]

• Replaces the embedded file support inside identity with support for the new static web assets feature.
• Removes the need to specify the bootstrap framework at runtime.
• Removes the need to embed static assets into the assembly.
• Removes the need to hijack the static file options to plug in the static assets.
• Copies only the assets for the selected version to the output folder on publish.

[ryanbrandenburg]

The ProjectTemplates parts of this seem fine, I'll leave reviewing the IdentityUI stuff to someone with more context.

[HaoK]

Removing the UIFramework runtime options is nice