Is there any way of getting a FTP inside Rstudio in order to work avoiding the connect-download-edit-save-connect-upload time consuming procedure of working on remote server?
RStudio itself doesn't have support for transparent working over FTP (like e.g. netrw), but you can do a couple of things to make this better:
Install RStudio Server on the remote server itself (then just access RStudio using a web browser), or
Set up a local folder on your machine which is synced to the remote server via third-party software, so that whenever you save locally it's automatically FTP'ed to the remote.
Hope that helps!