Update Week to Start on Monday

[winsmith]

Update the Calendar object used in DateOperations to start a week on Monday instead of Sunday.

This updates relative time intervals in queries to use Monday instead of Sunday as well.

[Jeehut]

Part of this, we had also discussed that the titles of the date picker options such as "This Week" and "Last Week" are somewhat unclear and can be misunderstood as "Last 7 Days". To clarify things, I suggested we add the sample dates such as "This Week (1st-6th)". I'll handle this aspect as part of this task as well.

[Jeehut]

@winsmith I've given the implementation of this a try with the following PR, but not very confident about things, please take a look:

• Add start of week as new option in models SwiftDataTransferObjects#36
• https://github.com/TelemetryDeck/web/pull/1741
• https://github.com/TelemetryDeck/telemetry/pull/421