Add RFC-2579 constants to rasn-smi

[jsatchell]

There are some constants in RFC-2579 (Textual conventions for SMI MIB 2) that might be useful to have somewhere, may be in rasn-smi, or possibly rasn-snmp. In the short term, I am thinking of the RowStatus values,but some of the others will surely be needed in time. The Row Status definition is:

Syntax INTEGER
active (1)
notInService (2)
notReady (3)
createAndGo (4)
createAndWait (5)
destroy (6)

Of these, the first three can be returned by a Get, while everything except notReady can be used in a Set operation. I imagined adding them as constants in rasn-smi::v2, with names like ROW_STATUS_ACTIVE, ROW_STATUS_NOT_IN_SERVICE and so on.

These values are needed for the utterly horrible way that rows in SNMP tables are created and managed.

If that is sane, I will raise an issue. If they should go somewhere else, or have different names, happy to take a hint!

This has become timely because I am now working on table support in my snmp agent.

[XAMPPRocky]

Thank you for your question, putting them in snmp makes sense