Add CFE_PSP_GetProcessorName() API

[jphickey]

Is your feature request related to a problem? Please describe.
The build configuration specifies a spacecraft ID, CPU/Processor ID, and a CPU/Processor Name, but the PSP API only gives runtime access to two of the three:

uint32 CFE_PSP_GetSpacecraftId   (void)
uint32 CFE_PSP_GetProcessorId    (void)

Describe the solution you'd like
Should add:

const char *CFE_PSP_GetProcessorName    (void)

Describe alternatives you've considered
Continue to offer incomplete information from PSP API.

Additional context
related to nasa/cFE#710

Requester Info
Joseph Hickey, Vantage Systems, Inc.

[skliper]

We should get this added in, such that the old defines can be deprecated. Old defines are very confusing at this point since they might be out of sync w/ what PSP is using.