As a user, I can use a "Tests evolution" gadget

A new JIRA gadget "Tests evolution" should provide a chart for showing the evolution of the status of the Tests, with a line for each status.
A special dotted line should be present, consisting of the number of total tests.

Aim: see the evolution/progress (accumulated status) of the tests, namely the ones belong to a Test Plan.

xx: date
yy: number of tests (not test runs)

Time period for xx axis: day, week, month

Date range:

• custom (start+end date), time range
• if "time range", then one of the following ones:
  • current week
  • last week
  • current month
  • last month

Show as table: flag (disable by default) for showing the results in a table view

Filters:

• saved filter (for finding Test Executions)
• saved filter (for finding Tests)
• test run's assignee, status
• test environment

Chart Title: by default "Tests Evolution" but may be customized