Add the Profile Sync Daemon Package & NixOS Module

Wasn't exactly sure what categories/subdirectories to put these under. It's a daemon that syncs your web browser profiles to tmpfs to increase speed/responsiveness & decrease ssd writes.
Would it be easy to make the package install all the binaries under /bin? It doesn't make much sense to have /usr in the package. If it's more than a setting, don't bother.