Add context.Context to more methods (#21546)

This PR adds a context parameter to a bunch of methods. Some helper
`xxxCtx()` methods got replaced with the normal name now.

Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

tests/integration/api_issue_reaction_test.go

@@ -82,7 +82,7 @@ func TestAPICommentReactions(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
 	comment := unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{ID: 2})
-	_ = comment.LoadIssue()
+	_ = comment.LoadIssue(db.DefaultContext)
 	issue := comment.Issue
 	_ = issue.LoadRepo(db.DefaultContext)
 	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: issue.Repo.OwnerID})