Move default config to librtemsdefaultconfig.a

An RTEMS application default configuration is contained in
cpukit/libmisc/dummy/default-configuration.c.  This default
configuration was contained in librtemscpu.a.  This had at least two
problems:

1. Application configuration errors may have pulled in the default
   configuration which in turn lead to multiply define symbols error.
   This was quite confusing.  You had to consult the linker map file to
   figure out what cased the pull in of the default configuration.  You
   needed to know what a linker map file is and how you generate it with
   your build system.  This was not very user friendly.

2. It prevented the use of default configuration items for each subsystem
   in librtemscpu.a.  This may be used to reduce the size of the
   configuration itself.

Move the default configuration to the separate library
librtemsdefaultconfig.a.

Close #3551.

cpukit/Makefile.am

@@ -281,7 +281,6 @@ librtemscpu_a_SOURCES += libmisc/cpuuse/cpuusagereset.c
 librtemscpu_a_SOURCES += libmisc/cpuuse/cpuusagetop.c
 librtemscpu_a_SOURCES += libmisc/devnull/devnull.c
 librtemscpu_a_SOURCES += libmisc/devnull/devzero.c
-librtemscpu_a_SOURCES += libmisc/dummy/default-configuration.c
 librtemscpu_a_SOURCES += libmisc/dummy/dummy-networking.c
 librtemscpu_a_SOURCES += libmisc/dumpbuf/dumpbuf.c
 librtemscpu_a_SOURCES += libmisc/fb/mw_print.c
@@ -1831,6 +1830,11 @@ $(top_srcdir)/sapi/src/version.c: version-vc-key.h
 
 all-local: generate-vc-key
 
+project_lib_LIBRARIES += librtemsdefaultconfig.a
+
+librtemsdefaultconfig_a_SOURCES =
+librtemsdefaultconfig_a_SOURCES += libmisc/dummy/default-configuration.c
+
 project_lib_LIBRARIES += libftpd.a
 
 libftpd_a_SOURCES =