Add PARAM_ALL setting for multi-option API parameters

Add PARAM_ALL setting for multi-option API parameters

Adds support for specifying an asterisk '*' instead of a pipe seperated list
of all the allowed options for a multi-option param.

Adds a line to the api help for these parameters.
Adds a "allspecifier" key to ApiParamInfo parameter responses
Enables the default ('*') for parameters of type 'namespace'.

Bug: T124009
Change-Id: I3905bb2516dc1ff982f1beeac3deed6b69446a77