Rename time 1HZ signal to ONEHZ

[jphickey]

Is your feature request related to a problem? Please describe.
In some environments, the CFE_TIME_ namespace prefix is not used.

When this prefix is removed from the 1HZ related identifiers (e.g. CFE_TIME_1HZ_CMD_MID) then one will be left with just 1HZ_CMD_MID ... and this is not a valid identifier in many contexts because it starts with a digit.

Describe the solution you'd like
Problem could be avoided if simply renamed to ONEHZ instead of 1HZ.

Additional context
This is really the only remaining symbol that has this concern, and its trivial to replace it. Can keep the old name as a deprecated symbol for backward compatibility.

Requester Info
Joseph Hickey, Vantage Systems, Inc.