extend technical datasheet with more details about SNMP

The technical datasheet needs to state

• SNMP implements "GetBulk" operation
• using specific service it is possible to specificaly disable "GetBulk"
• "GetBulk" is used by tools, however it may lead to security scanners showing vulnerabilities for the implementation

In addition, the following modification is required

• add footnote to "SNMP V1" in table row "Topology recognition" stating that SNMP can be completely disabled by the user if desired
• delete the sentence "Conformance Class A devices can not be build because SNMP can not be disabled" from section restrictions and limitations

The description for the technical data sheet of the SNMP functions and options are part of the PN CORE (PNS/PNM) PSPNCORE-739 .
Therefore the changes can be found in the PNCORE svn repository.