BUG: 183429
Added option allowing user to choose if they would want to open
externally called files/directories in new tabs. This option is enabled by default.
When this option is selected externally called files/directories are opened in a a new tab of an instance of Dolphin that already exists. If there is no instance then the files/directories are opened in a new window. The newly opened file/directory has its tab activated, and consequently, the window is also activated.
When the user clicks "Open In New Window" or "Detach Tab", the files/directories are opened in a new window, regardless of the setting chosen.