Update Quality pipeline oncall rotation for better time zone coverage

Why is this change being made?

Updates the Quality pipeline oncall rotation to provide for better time zone coverage.

Please note, under this new system there are two DRI and two Secondaries each week. The DRIs are intended to be in offset time zones, each with a secondary in a similar time zone to themselves.

SETs are on call approximately once every 6 weeks. EPEs are on call every other month during planning week. QEMs and DoQ (Director of Quality) are on call during planning week approximately once every 5 months. Though this change increases the frequency of being on call, the workload while on call should be spread out a little better so it's not quite so hectic.

If you want to visualize this differently, please see the spreadsheet used for planning this out: https://docs.google.com/spreadsheets/d/1c8_Hrfba7R-2xV4jF0BiodkdCqR77Cyx1YPuxVM7sBw/edit#gid=0&range=A36 (this MR has iterated past the work in this spreadsheet)

Closes https://gitlab.com/gitlab-org/quality/team-tasks/issues/338

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what