Added support to Push to multiple Cloudlog instances

[DJLax5]

Why did I make these changes?

I am part of a university club station. And we now have more than one HAM who uses CLoudlog and wants to log their QSOs made from our club station. But, as we have multiple people wanting to log into different cloudlog instances, we needed a solution. For this, I changed the settings window, so that CloudlogCAT would push the current mode and frequency to multiple cloudlog instances.

How does it work?

I tried to make it as intuitive as possible. Down below you can see a screenshot of the new settings window. On the left hand side, there is a list of the current cloudlog instances setup. The + and - buttons add and remove a target.
The textboxes on the right are filled automatically by selecting a target. Their functionality:

• Title: The Title of the Target displayed in the list, and for error messages
• Radio Name: The radio name displayed in cloudlog. The default "OmniRig" Radio can now be replaced per user.
• Address / Key: The URL and key as bevor
• Active: If this box is not checked, this target is ignored but still saved.

Features and known limitations

• Compatible with the former settings file. This can be installed as an update and will read the previous settings config file just fine.
• Tested and no known bugs (That does not mean there aren't any...)
• The radio name in cloudlog is appended by 1 or 2 depending on the rig selection radio button.
• The config file is no longer human-readable. The list is serialized using a binary formatter.
• Errors are only displayed for the first failed target.
• I increased the version number to 1.3.1.0. I don't know your version numbering policy, so feel free to change it.

Disclaimer

Please, test it thoroughly before merging!
I am by no means an expert in VB.NET and never used Visual Studio together with git. I may have committed local Visual Studio files which I shouldn't have.
If you don't feel like merging my PR, that's fine. Maybe just add a link to my fork or something like that.

P.S.: Thanks for all your work with Cloudlog!