Allow dynamic configuration of inner properties of hub devices

[glopesdev]

Currently hub devices expose as public properties each of their internal devices for configuration. However, this makes it hard to dynamically assign properties to individual devices as inner properties cannot be directly externalized into the workflow (see bonsai-rx/bonsai#1879).

The only option right now is to create copy constructors in each of the internal device configuration operators that allows constructing a new instance directly from values passed in the property mapping. For example, the following workflow would work to replace the Heartbeat configuration of the breakout:

Workflow

<?xml version="1.0" encoding="utf-8"?>
<WorkflowBuilder Version="2.8.1"
                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xmlns:onix="clr-namespace:OpenEphys.Onix;assembly=OpenEphys.Onix"
                 xmlns:scr="clr-namespace:Bonsai.Scripting.Expressions;assembly=Bonsai.Scripting.Expressions"
                 xmlns="https://bonsai-rx.org/2018/workflow">
  <Workflow>
    <Nodes>
      <Expression xsi:type="Combinator">
        <Combinator xsi:type="onix:CreateContext">
          <onix:Driver>riffa</onix:Driver>
          <onix:Index>0</onix:Index>
        </Combinator>
      </Expression>
      <Expression xsi:type="Combinator">
        <Combinator xsi:type="IntProperty">
          <Value>0</Value>
        </Combinator>
      </Expression>
      <Expression xsi:type="scr:ExpressionTransform">
        <scr:Expression>new(
True as Enable,
it as BeatsPerSecond)</scr:Expression>
      </Expression>
      <Expression xsi:type="PropertyMapping">
        <PropertyMappings>
          <Property Name="Heartbeat" Selector="Enable,BeatsPerSecond" />
        </PropertyMappings>
      </Expression>
      <Expression xsi:type="Combinator">
        <Combinator xsi:type="onix:ConfigureBreakoutBoard">
          <onix:Name>BreakoutBoard</onix:Name>
          <onix:Heartbeat>
            <onix:DeviceName>BreakoutBoard/Heartbeat</onix:DeviceName>
            <onix:DeviceAddress>0</onix:DeviceAddress>
            <onix:Enable>true</onix:Enable>
            <onix:BeatsPerSecond>10</onix:BeatsPerSecond>
          </onix:Heartbeat>
          <onix:AnalogIO>
            <onix:DeviceName>BreakoutBoard/AnalogIO</onix:DeviceName>
            <onix:DeviceAddress>6</onix:DeviceAddress>
            <onix:Enable>true</onix:Enable>
            <onix:InputRange0>TenVolts</onix:InputRange0>
            <onix:InputRange1>TenVolts</onix:InputRange1>
            <onix:InputRange2>TenVolts</onix:InputRange2>
            <onix:InputRange3>TenVolts</onix:InputRange3>
            <onix:InputRange4>TenVolts</onix:InputRange4>
            <onix:InputRange5>TenVolts</onix:InputRange5>
            <onix:InputRange6>TenVolts</onix:InputRange6>
            <onix:InputRange7>TenVolts</onix:InputRange7>
            <onix:InputRange8>TenVolts</onix:InputRange8>
            <onix:InputRange9>TenVolts</onix:InputRange9>
            <onix:InputRange10>TenVolts</onix:InputRange10>
            <onix:InputRange11>TenVolts</onix:InputRange11>
            <onix:Direction0>Input</onix:Direction0>
            <onix:Direction1>Input</onix:Direction1>
            <onix:Direction2>Input</onix:Direction2>
            <onix:Direction3>Input</onix:Direction3>
            <onix:Direction4>Input</onix:Direction4>
            <onix:Direction5>Input</onix:Direction5>
            <onix:Direction6>Input</onix:Direction6>
            <onix:Direction7>Input</onix:Direction7>
            <onix:Direction8>Input</onix:Direction8>
            <onix:Direction9>Input</onix:Direction9>
            <onix:Direction10>Input</onix:Direction10>
            <onix:Direction11>Input</onix:Direction11>
          </onix:AnalogIO>
          <onix:DigitalIO>
            <onix:DeviceName>BreakoutBoard/DigitalIO</onix:DeviceName>
            <onix:DeviceAddress>7</onix:DeviceAddress>
            <onix:Enable>true</onix:Enable>
          </onix:DigitalIO>
          <onix:MemoryMonitor>
            <onix:DeviceName>BreakoutBoard/MemoryMonitor</onix:DeviceName>
            <onix:DeviceAddress>10</onix:DeviceAddress>
            <onix:Enable>false</onix:Enable>
            <onix:SampleFrequency>10</onix:SampleFrequency>
          </onix:MemoryMonitor>
        </Combinator>
      </Expression>
      <Expression xsi:type="Combinator">
        <Combinator xsi:type="onix:StartAcquisition">
          <onix:ReadSize>2048</onix:ReadSize>
          <onix:WriteSize>2048</onix:WriteSize>
        </Combinator>
      </Expression>
    </Nodes>
    <Edges>
      <Edge From="0" To="4" Label="Source1" />
      <Edge From="1" To="2" Label="Source1" />
      <Edge From="2" To="3" Label="Source1" />
      <Edge From="3" To="4" Label="Source2" />
      <Edge From="4" To="5" Label="Source1" />
    </Edges>
  </Workflow>
</WorkflowBuilder>

Assuming that the ConfigureHeartbeat class defines the following copy constructor:

public ConfigureHeartbeat(bool enable, uint beatsPerSecond)
    : base(typeof(Heartbeat))
{
    Enable = enable;
    BeatsPerSecond = beatsPerSecond;
}