Scan integration of Lambda detectors

This is a Lambda entry in online.xml:

<!-- old lambda server before feb 2021 
Server name: Lambda
--> 
<device>
 <name>lambda</name>
 <type>DETECTOR</type>
 <module>lambda</module>
 <device>p99/lambda/exp.01</device>
 <control>tango</control>
 <hostname>haspp99mono:10000</hostname>
</device>

<!-- new lambda server after feb 2021 
Server name: LambdaCtrl (LambdaRecv follows)
LambdaRecv can also run without the LambdaCtrl
-->
<device>
 <name>lambda</name>
 <type>DETECTOR</type>
 <module>lambda</module>
 <device>p99/lambdactrl/01</device>
 <control>tango</control>
 <hostname>haspp99mono:10000</hostname>
</device>

FileStartNum, SaveFilePath and FilePrefix can be set via a pre-scan hook (13.2.1).