Bug fixes and improvements

[mpotra]

This PR fixes a few bugs:

• Path inside Introspect should be a binary instead of an atom
• Marshaling an array of bytes ({array, byte}), when binary payload given: just use the binary, instead of converting the binary to a list of chars and marshal the list (perf issues with large binaries)
• On DBus Hello reply, store the unique name and allow later retrieving it
• Allow ServiceReg argument to be a PID, when creating a dbus_connection_peer
• in dbus_service_reg to route replies to the registered ServiceName when the destination header field supplies one; fallback to the default service if not.

[jeanparpaillon]

Thank you for this PR. I've not been touching this code for years, thank you for your care :)

[mpotra]

@jeanparpaillon would it be possible to have a hex release as well? :pray: (once merged, OFC)

[jeanparpaillon]

@mpotra have you identified other missing features/bugs that should be in the release ?

[mpotra]

Many thanks @jeanparpaillon for the merge! No, I haven't identified anything additional for this release, but will keep an eye out and do more PRs here if I do