Move the virsh tool and its man page into the tools directory

* Makefile.am: Remove rules for virsh.1 man page
* virsh.1: Remove auto-generated file
* docs/Makefile.am: Remove rules for virsh.pod man page
* docs/virsh.pod: Move to tools/ directory
* src/Makefile.am, src/.gitignore: Remove rules for virsh
* src/console.c, src/console.h, src/*.ico, src/virsh_win_icon.rc,
  src/virsh.c: Move into tools/ directory
* tools/Makefile.am: Add rules for building virsh
* tools/.gitignore: Ignore virsh built files
* tests/virshtest.c, tests/int-overflow: Update for new
  virsh location