Convert all categories and modules into static lists

Remove the complicated mechanism that could be (in theory) used by
external libraries to register new categories and modules with
statically defined lists in <isc/log.h>.  This is similar to what we
have done for <isc/result.h> result codes.  All the libraries are now
internal to BIND 9, so we don't need to provide a mechanism to register
extra categories and modules.

doc/dev/dev.md

@@ -1076,7 +1076,7 @@ the following steps need to be taken to initialize it.
    the DNS library, include the following:
 
         #include <isc/log.h>
-        #include <dns/log.h>
+        log.h>/log.h>
 
 1. Initialize a logging context.  A logging context needs a valid
    memory context in order to work, so the following code snippet shows a