If you are using Sense on-premise (either Enterprise or Desktop) you will want to use the Qlik Web Connectors add on. This provides a web based configuration tool which then acts as a proxy between Sense (or QlikView) and various different data sources - including FTP sources.
SFTP can be a bit tricky, if you have to exchange client certificates, but it can be done.
You can licence Qlik Web Connectors with a Qlik Sense Enterprise licence key (a recent one) so you can get to the premium connectors as well as the free ones (of which FTP/SFTP is one).
Not sure why you would be using FTP for GA? There is a specific GA connector included with QWC, or you can talk to it using the standard REST connector and crafting your own API calls.
What do you mean by 'share files'? The Qlik Web Connectors allow you to upload files to FTP from the load script, as well as to download them. In this way you can create files and FTP them to a server. This is something that developers can do though, rather than users.
For user access to FTP sharing I would look at some other solution.