Use GitLab for FE scheduling

We want to use GitLab for FE scheduling and regression tracking/improvement (right now we still use a google spreadsheet and the gitlab issues list). But in order for us to use GitLab, we need a few more features.

Features requested

1. Issue board with a configuration/filter scoped and associated to the entire board (#2518 (closed))

• Eg. frontend Deliverable issue board list or a frontend regression issue board list

1. Sorting in issue board list (https://gitlab.com/gitlab-org/gitlab-ee/issues/3042)

• So that we can sort by assignees (so it's easier to see whether a person on the FE team is over-assigned or not)

1. Burndown charts view for multiple labels (https://gitlab.com/gitlab-org/gitlab-ee/issues/3044)

• We should start with just a single label
• Eg. Burndown chart for milestone %10.0 for frontend Deliverable
• So that we can easily track the work done by the FE team in a single milestone
• Easier for scheduling team to highlight issues that are frontend Deliverable that are not completed (late in the milestone)

Current workflow

1. PM Labels issues as Deliverable and sets milestone
2. FE Scheduling team goes through each Deliverable and labels frontend and assigns accordingly
3. FE Scheduling team updates the google spreadsheet to track who is assigned to what