docs/integration.rst: Also list the required host tools
docs/integration.rst: Also list the required host tools

Similar to the target tool requirements, there is also a list of host
tools that must be available in order to allow building bundles with
RAUC etc.

Signed-off-by: Enrico Jorns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

rauc/rauc,jluebbe/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc,rauc/rauc,ejoerns/rauc,rauc/rauc,ejoerns/rauc