appview/repo: remove EmailToDidOrHandle
we no longer resolve handles from DIDs at the handlers, we do this
dynamically when rendering the templates. EmailToDidOrHandle did not
follow this pattern.
there were a few negative side effects from this: the `tinyAvatar`
helper requires that the input be a DID; and not a handle. when a handle
is passed, it results in a different default color for users without
profile pictures; resulting in different colors in repo-log versus, say,
the topbar.
Signed-off-by: oppiliappan <me@oppi.li>