Issues overview should not show issues from archived repos (#13220)

* Add lots of comments to user.Issues()

* Answered some questions from comments

* fix typo in comment

* Refac user.Issues(): add func repoIDs

* Refac user.Issues(): add func userRepoIDs

* Refac user.Issues(): add func issueIDsFromSearch

* Refac user.Issues(): improve error handling

* Refac user.Issues(): add inline documentation and move variable declarations closer to their usages

* Refac user.Issues(): add func repoIDMap

* Refac user.Issues(): cleanup

* Refac: Separate Issues from Pulls during routing

* fix typo in comment

* Adapt Unittests to Refactoring

* Issue13171: Issue and PR Overviews now ignore archived Repositories

* changed some verbatim SQL conditions to builder.Eq

* models/issue.go: use OptionalBool properly

Co-authored-by: 6543 <6543@obermui.de>

* Use IsArchived rather than ExcludeArchivedRepos

* fixed broken test after merge

* added nil check

* Added Unit Test securing Issue 13171 fix

* Improved IsArchived filtering in issue.GetUserIssueStats

* Removed unused func

* Added grouping to avoid returning duplicate repo IDs

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Gitea <gitea@fake.local>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

models/fixtures/issue.yml

@@ -147,3 +147,28 @@
   is_pull: true
   created_unix: 1602935696
   updated_unix: 1602935696
+
+
+-
+  id: 13
+  repo_id: 50
+  index: 0
+  poster_id: 2
+  name: issue in active repo
+  content: we'll be testing github issue 13171 with this.
+  is_closed: false
+  is_pull: false
+  created_unix: 1602935696
+  updated_unix: 1602935696
+
+-
+  id: 14
+  repo_id: 51
+  index: 0
+  poster_id: 2
+  name: issue in archived repo
+  content: we'll be testing github issue 13171 with this.
+  is_closed: false
+  is_pull: false
+  created_unix: 1602935696
+  updated_unix: 1602935696