Utilise buildpack app settings auto reconfiguration rather than CloudFoundry.Configuration

This PR simplifies the monitor-bot project as follows

1.  Removes the `CloudFoundry.Configuration` projects in favour of the [.net-buildpack's AppSettingsAutoReconfiguration autoconfiguration](https://github.com/cloudfoundry-community/.net-buildpack/issues/26).  appSettings values are automatically overwritten by matching ENV variables when deployed to Cloud Foundry
2.  Removes the compiliation of the `src/` folder during the Cloud Foundry staging process.  You are expected to upload compiled .NET binaries rather than .NET src/
3.  Monitors can be enabled / disabled using appSettings

```xml
<appSettings>
    <add key="StaticPageMonitor" value="true" />
    <add key="StreamingLatencyMonitor" value="false" />
    <add key="AllServiceMonitor" value="false" />
```
This enables monitors to be enabled / disabled in a bot running on CF using a call like `cf set-env ciapi-latency-monitor-VERSION AllServiceMonitor true --restart`