Support not sending system title in GeneralGlobalCipher APDU

[Krolken]

Local communications on Pietro Fiorentini RSE gas meters do not use the system title in general-glo-ciphering APDU.

It is questionable if this is correct behaviour but we need to be pragmatic and solve it.

The system title is till used for the ciphered text, otherwise the encryption is not done correctly.

GeneralGlobalCiphering APDU is created in DlmsConnection.protect() and it would be possible to omit the system title but there also needs to be changes in the APDU class to allow for system_title=None and to encode it correctly into the byte representation.

This should not be default behaviour and we should introduce an optional argument to the DlmsConnection that handles complext settings for the connection. This could also adress the problem in #70
The more meters we aim to support the the more special cases we will find and it is better to have a serialziable object so we can easily transfer the settings in different environments and use cases.

For example

DlsmConnectionSettings:
   empty_system_title_in_general_glo_ciphering_apdu: bool = field(default=False)