Issues to apply severity and priority for Quality

Here is a list of issues without severity and priority:

• Remove User.existing_member? ~"Manage", Quality, backend, ~"backstage", ~"technical debt"
• WIP: Test Plan for Add member counts to GitLab.com billing areas ~"Manage", Quality, gitlab.com, ~"test plan"
• WIP: Test plan for Implement Smartcard/CAC Authentication in GitLab ~"Manage", Quality, admin dashboard, authentication, ~"devops:manage", ~"test plan"
• Test Plan for "Close and reopen epics with buttons" ~"Plan", Quality, ~"devops:plan", epics, ~"test plan"
• Test Plan for 'Quick action to add/remove issue to epic from issue' ~"Plan", Quality, ~"test plan"
• Test Plan for "Milestone dates integrated into epics" ~"Plan", Quality, ~"test plan"
• Test plan for Group-level project templates ~"Manage", Quality, ~"devops:administration", ~"project templates", ~"test plan"
• Test plan for "Show file code owners when viewing a file" Quality, ~"test plan"
• Test plan for Reviews: batch comments on merge requests Quality, ~"test plan"
• [Rails5] Couldn't find User with 'id'=1289 Quality, backend, ~"dependency update", rails5, test
• EE test jobs time out Quality, ~"broken master", ci-build, test
• Extract EE specific files/lines for YAML files Quality
• Configure Gitlab QA for review apps QA, Quality, ~"review apps"
• Ensure EE Review Apps cluster is big enough (or even autoscaled) and Review Apps are automatically cleaned up after x days Quality, ~"review apps"
• Transient order-dependent failure in spec/features/merge_request/user_merges_when_pipeline_succeeds_spec.rb Quality, ~"broken master"

/cc @meks