Insteon: Insert PLM Controller Link in MH Hash of ALDB Records During I2CS Linking

The current I2CS linking routine puts both the PLM and Device into linking mode to create the PLM->device links.  Essentially, this performs a manual linking.  After the linking process MH scans the device's link table (because prior to this link, the device would not respond to MH so we have no idea what is contained in its link table).

However, as Michael identified about a month ago, the controller record on the PLM was never added to MH's cache of the PLM ALDB.  Scanning the entire PLM after a linking process would likely be very annoying.  The failure to insert the data into the hash was likely benign, but never know.

This branch solves the omission, by obtaining the device category and firmware details from the ALL-Linking Complete message.  The solution is nifty in that it is able to rely on the devcat and firmware routines that have remained in the code, but not used for some time.  The result is that MH now inserts an accurate representation of the previously omitted link into the cache.