Fix missing dc power and xnetxocket enums.

[reckenro]

What does this Pull Request accomplish?

DCPower:

• Event enum referenced by WaitForEvent and WaitForEventWithChannels
• SendSoftwareEdgeTriggerType enum referenced by SendSoftwareEdgeTrigger and SendSoftwareEdgeTriggerWithChannels
• SessionState enum removed from metadata. Couldn't find any reference to it or its values anywhere, including header file.

XNETSocket:

• ProtocolFamily enum removed from metadata. It could arguably be used for domain param of nxsocket instead of AddressFamily enum but their values match, are often used interchangeably in implementations, and AddressFamily (nxAF _INET) is what's referenced in the documentation.

Why should this Pull Request be merged?

Addresses the 3 enums in dc power not included in proto and 1 enum in xnetsocket not in the proto.

AB#1991309
AB#1991312

What testing has been done?

Visual inspection of generated proto files. Relying on unit tests since functions now referencing enums aren't used in system tests or examples.

[reckenro]

Note: Marking breaking change as the client will need to update the enum their using for the updated DC Power functions.

[reckenro]

@mgumble , same as the FGEN enum one. Pretty straightforward so I'm going to remove you but feel free to come back to it if you want when you get back.