nodedev: Convert virNodeDeviceObjListPtr to use hash tables

nodedev: Convert virNodeDeviceObjListPtr to use hash tables

Rather than use a forward linked list of elements, it'll be much more
efficient to use a hash table to reference the elements by unique name
and to perform hash searches.

This patch does all the heavy lifting of converting the list object to
use a self locking list that contains the hash table. Each of the FindBy
functions that do not involve finding the object by it's key (name) is
converted to use virHashSearch in order to find the specific object.
When searching for the key (name), it's possible to use virHashLookup.
For any of the list perusal functions that are required to evaluate
each object, the virHashForEach function is used.