[FEATURE REQUEST] Import custom converters

[devaskim]

Now to add new custom converter or update existing one on a production gateway I need somehow (ftp, scp and etc.) copying it and then reboot the gateway.

As a user I want to have more convenient way of doing these operations and ideally without gateway/connector reboot.

For example, it might be Server-side RPCs to list custom converters and export/import theirs source code. To make this feature even more powerful it would be great to have simple code editor widget on a server side as it is already done for JS/CSS/HTML.

To reload custom converters it might be separate RPC. So updating the converter might stay 2-phase operation