Add a control on the extended DO that reuse standard DO names

[ADehouck]

IEC 61850 standard stands that DO names can be reused in exentions (either for additionnal DO in standard LN, or DO in extended LN)

In this case, the DO shall have the same meaning, which means that:

• if the DO is usually not Omulti, it should not be instanciated in extensions
• the CDC shall be identical to the standard one

Example :

The DO "HeatAlm" id defined in SPTR, and has the meaning "If true, the supervision has detected an abnormal state of the heater."

It is possible to extend a standard LN (for example SPRS) with this DO "HeatAlm", or to use it in a private extended LN "USER"

but in these cases:

• it shall also be a cdc = "SPS"
• it is not allowed to instanciate it : "HeatAlm1, HeatAlm2..."