Add job-filtering spec.

Add spec checking whether EmployersApplyingJobseekersByJobReportGenerator filters out jobs that the given employer did not post.
Add TODOs to notes.txt.
Merge branch 'new_notes'.
Make very large test pending.

Make very large test pending until we can divide it into more atomic tests first.
Split out mis-grouped specs.

Split specs for JobseekerAndJobsReport into their own section, as they test a distinct functionality.
More concise setup.

Make setup for JobseekerAndJobsReport specs more concise, falling back to more defaults.
Move all spec setup and helpers after their tests.
Remove premature specs.

Remove specs for EmployersApplyingJobseekersByJobReportGenerator, as we need to spec and build out the component parts first and separately.