Use `go:embed` for serving static UI files

Now that we are using `go1.16`, we can refactor the static asset server to use `go:embed` rather than `go-bindata`.

Start by locating the static asset server and the current go-bindata generation or integration in the repository. Read the existing Go 1.16 build path and verify how the UI assets are served before changing the asset mechanism. Done means the static UI remains available using go:embed and the old go-bindata path is no longer required.

Written by the indexing model from the issue text.