package/open62541: cleanup tools files after installation

package/open62541: cleanup tools files after installation

The open62541 tools directory is indeed 52 MiB, which built as a standalone package
named 'libopen62541-1-tools' in launchpad. Nothing is required at runtime.

See the official debian control file template:
https://raw.githubusercontent.com/open62541/open62541/master/debian/control-template

See https://launchpad.net/~open62541-team/+archive/ubuntu/ppa/+packages
libopen62541-1       Open source implementation of OPC UA - shared library
libopen62541-1-dev   Open source implementation of OPC UA - development files
libopen62541-1-tools Open source implementation of OPC UA - tools
open62541-doc        Open source implementation of OPC UA - documentation

Signed-off-by: Scott Fan <fancp2007@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>