/issues page UI requires improvement

[KazzmanK]

Feature Description

When you have a lot of repositories in GITEA_ROOT/issues you can click on the left to select and unselect repositories to include or exclude issues from different repositories.

But during select/unselect page reloads and scroll is jumping.

Expected behavior is

• split page into two independent scrolling panes - for repositories and issues
• update right pane with issues dynamically, without page reload
• have url updated with selected repositories to make it possible to create a shortcut with interested repo

Screenshots

No response