Moved topics to other pages

doc/subscriptions/bronze_starter.md

doc/user/project/issues/img/issue_search_by_id_v15_0.png

doc/user/project/issues/managing_issues.md

doc/user/project/labels.md

..._requests/img/filter_approved_by_merge_requests_v14_6.png

...rge_requests/img/filter_approver_merge_requests_v14_6.png

...e_requests/img/filtering_merge_requests_by_date_v14_6.png

...sts/img/filtering_merge_requests_by_environment_v14_6.png

doc/user/project/merge_requests/index.md

doc/user/project/merge_requests/methods/index.md

doc/user/project/milestones/index.md

doc/user/project/working_with_projects.md

doc/user/search/img/dashboard_links_v14_6.png

doc/user/search/img/issues_mrs_shortcut_v14_6.png

doc/user/search/index.md

doc/user/todos.md