Fix various problems around projects board view (#30696)

# The problem
The previous implementation will start multiple POST requests from the
frontend when moving a column and another bug is moving the default
column will never be remembered in fact.

# What's changed

- [x] This PR will allow the default column to move to a non-first
position
- [x] And it also uses one request instead of multiple requests when
moving the columns
- [x] Use a star instead of a pin as the icon for setting the default
column action
- [x] Inserted new column will be append to the end
- [x] Fix #30701 the newly added issue will be append to the end of the
default column
- [x] Fix when deleting a column, all issues in it will be displayed
from UI but database records exist.
- [x] Add a limitation for columns in a project to 20. So the sorting
will not be overflow because it's int8.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/issue/issue.go

@@ -42,7 +42,7 @@ func NewIssue(ctx context.Context, repo *repo_model.Repository, issue *issues_mo
 			}
 		}
 		if projectID > 0 {
-			if err := issues_model.ChangeProjectAssign(ctx, issue, issue.Poster, projectID); err != nil {
+			if err := issues_model.IssueAssignOrRemoveProject(ctx, issue, issue.Poster, projectID, 0); err != nil {
 				return err
 			}
 		}