DeleteUnusedBranchesForm: add Settings button to directly go to corresponding plugin settings page
DeleteUnusedBranchesForm: set minimum size for dialog
BackgroundFetchPlugin: if invoked via menu show SettingsDialog instead of doing nothing
Merge pull request #1925 from feinstaub/feature/goto_plugin_settings

Open corresponding SettingsPage directly from Plugin
When FormGotoCommit and clipboard data is used select all text in textbox

=> if user starts typing the textbox is cleared at first
Merge pull request #1930 from feinstaub/fix_gotocommit

When FormGotoCommit and clipboard data is used select all text in textbox