Ability to use relative dates in BrewwQL for weekly reporting - such as 'start of last week'

The ability to use relative dates in BrewwQL such as ‘start of last week’, ‘end of last week’ and ‘start of next week’ etc.

This can now be done :tada: For options, please see the dates section of Introduction to BrewwQL.

We opted for Monday last week rather than Start of last week as some people (or countries) consider the start of the week as Monday and others as Sunday, so this way avoids any confusion here.