Perf-o-matic: generate dashboard images for 30, 90, and 365 days

Perf-o-matic: generate dashboard images for 30, 90, and 365 days
https://bugs.webkit.org/show_bug.cgi?id=80016

Reviewed by Eric Seidel.

Add the ability to generate graphs for 30, 90, and 365 day graphs but only occasionally
according to the heuristics in DashboardImage.needs_update.

Also fix a bug in Runs.chart_params that y-axis grid was set to an incorrect value.

* Websites/webkit-perf.appspot.com/controller.py:
(schedule_runs_update):
(RunsChartHandler.post):
* Websites/webkit-perf.appspot.com/json_generators.py:
(Runs.chart_params):
* Websites/webkit-perf.appspot.com/json_generators_unittest.py:
(RunsTest.test_chart_params_with_value):
* Websites/webkit-perf.appspot.com/models.py:
(DashboardImage):
(DashboardImage.needs_update):
* Websites/webkit-perf.appspot.com/models_unittest.py:
(HelperTests._assert_there_is_exactly_one_id_holder_and_matches):
(HelperTests.test_create_in_transaction_with_numeric_id_holder.execute):
(HelperTests.test_create_in_transaction_with_numeric_id_holder):
(HelperTests.test_failing_in_create_in_transaction_with_numeric_id_holder):
(HelperTests.test_raising_in_create_in_transaction_with_numeric_id_holder):
(HelperTests.test_delete_model_with_numeric_id_holder.execute):
(HelperTests.test_delete_model_with_numeric_id_holder):
(HelperTests.test_model_from_numeric_id.execute):
(HelperTests):
(HelperTests.test_model_from_numeric_id):
(BranchTests.test_create_if_possible):
(PlatformTests.test_create_if_possible):
(BuilderTests.test_create):
(BuilderTests.test_update_password):
(BuilderTests.test_hashed_password):
(BuilderTests.test_authenticate):
(_create_some_builder):
(_create_build):
(BuildTests.test_get_or_insert_from_log):
(TestModelTests.test_update_or_insert):
(TestModelTests.test_update_or_insert_to_update):
(TestModelTests.test_merge):
(TestResultTests.test_get_or_insert_value):
(TestResultTests.test_get_or_insert_stat_value):
(TestResultTests.test_replace_to_change_test_name):
(TestResultTests.test_replace_to_change_test_name_with_stat_value):
(TestResultTests.test_replace_to_change_test_name_overrides_conflicting_result):
(ReportLogTests._create_log_with_payload):
(ReportLogTests.test_builder):
(ReportLogTests.test_branch):
(ReportLogTests.test_platform):
(PersistentCacheTests._assert_persistent_cache):
(PersistentCacheTests.test_set):
(PersistentCacheTests.test_get):
(DashboardImageTests):
(DashboardImageTests.test_needs_update):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@109418 268f45cc-cd09-0410-ab3c-d52691b4dbfc