c-icap: new package

[Thomas:
 - Remove trailing whitespace everywhere
 - Rewrap the Config.in help text
 - Fix Config.in comment, the proper text for BR2_PREFER_STATIC_LIB is
   "dynamic library", not "libdl library"
 - Use a PID file in the init script
 - Show OK / FAIL when stopping the service
 - Remove the largefile/IPv6 handling in c-icap.mk, since they are now
   mandatory. We therefore pass --enable-large-files and --enable-ipv6
   unconditionally.
 - Remove the reference to a non-existing
   C_ICAP_INSTALL_TARGET_CONFIGS install target hook.
 - Install the init script unconditionally.
 - Remove unneeded example configuration files (*.default) from /etc,
   and fixup the c-icap.conf so that the default values work with
   Buildroot
 - Properly handle the *-config scripts installed by c-icap.
 - Add hash file.]

Signed-off-by: Guillaume GARDET <guillaume.gardet@oliseo.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>