Fix ArgumentException in ConsoleUI recommendations

[HebaruSan]

Problem

If you have a lot of modules installed, ConsoeUI's "audit recommendations" option can throw an exception:

[ERROR] FATAL UNHANDLED EXCEPTION: System.ArgumentException: An item with the same key has already been added. Key: NearFutureConstruction 1.1.4
  at System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) [0x0015a] in <c4bddbfe864a4b8191bb818d6b204e9d>:0 
  at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <c4bddbfe864a4b8191bb818d6b204e9d>:0 
  at CKAN.ConsoleUI.DependencyScreen.generateList (System.Collections.Generic.HashSet`1[T] inst) [0x001f4] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.DependencyScreen..ctor (CKAN.KSPManager mgr, CKAN.ConsoleUI.ChangePlan cp, System.Collections.Generic.HashSet`1[T] rej, System.Boolean dbg) [0x000ee] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.ModListScreen.ViewSuggestions () [0x0008d] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.Toolkit.ConsolePopupMenu.Run (System.Int32 right, System.Int32 top) [0x00162] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.Toolkit.ConsoleScreen.<.ctor>b__0_1 (System.Object sender) [0x00023] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.Toolkit.ScreenContainer.Interact () [0x0003e] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.Toolkit.ScreenContainer.Run (System.Action process) [0x0002b] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.ConsoleCKAN..ctor (CKAN.KSPManager mgr, System.Boolean debug) [0x0005b] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.ConsoleUI.ConsoleUI.Main_ (System.String[] args, CKAN.KSPManager manager, System.Boolean debug) [0x00007] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.CmdLine.MainClass.ConsoleUi (CKAN.KSPManager manager, CKAN.CmdLine.CommonOptions opts, System.String[] args) [0x00019] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.CmdLine.MainClass.RunSimpleAction (CKAN.CmdLine.Options cmdline, CKAN.CmdLine.CommonOptions options, System.String[] args, CKAN.IUser user, CKAN.KSPManager manager) [0x002ff] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.CmdLine.MainClass.Execute (CKAN.KSPManager manager, CKAN.CmdLine.CommonOptions opts, System.String[] args) [0x0028b] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 
  at CKAN.CmdLine.MainClass.Main (System.String[] args) [0x000a1] in <ce28b1fd8caa4b339aed683ae3b21ffc>:0 

Reported in #2986 (comment) .

Cause

ModuleInstaller.FindRecommendations can return a module in the suggested-by list that's also in the recommendations or sugggestions.

ConsoleUI.DependencyScreen puts all three lists into one dictionary keyed by the CkanModule, which causes exceptions to be thrown on duplicates.

Changes

Now ModuleInstaller.FindRecommendations excludes recommended and suggested modules from the supported-by list. No module will appear in more than one of the lists.