Display git-bug identity avatars

Amolith opened

git-bug identities have metadata, a piece of which contains the URL to their avatar. We should be able to use AvatarUrl() to obtain it in pkg/web/webui_bugs.go and render them (SAFELY!) in pkg/web/templates/bug.html and pkg/web/templates/bugs.html

entities/identity/identity.go

// AvatarUrl return the last version of the Avatar URL
func (i *Identity) AvatarUrl() string {
	return i.lastVersion().avatarURL
}

Amolith closed the bug