Create a "Download file URL" formatter

Hey, I just prepared MR for a similar issue. 'URL Only' and 'URL Plain' options are now available for the existing FieldFormatter Plugin. Probably this issue may be closed.

@Panchuk I don't think we should close this, but should perhaps postpone this on your issue and maybe you'd like to incorporate the settings mentioned in the proposed resolution afterwards?

@Anybody Yep, using the existing formatter we can output the URL as plain text, but there is no way to choose an absolute/relative option.

Here a two options:

1) Add new options to the existing formatter plugin.
2) Create another formatter that extends FileUriFormatter logic.

@Panchuk what would you prefer? And should we add that to your issue or do it here afterwards?

@Anybody I think it better to create a second formatter plugin. I'll prepare MR for this issue soon.

I've created a new field formatter plugin according to the requirements in the issue body. Can somebody review the code and test this feature?