Add example script for loading historical data

[defanator]

For the record, here's the 1st iteration of fetching 11 months data without filtering duplicate datapoints:

2023-11/export.out:2024-10-15 17:22:44,481 [INFO] export_timeseries.py: ========[ 36 metrics, 1407174 values, oldest @ 1698929928 2023-11-02 16:58:48, newest @ 1701374340 2023-11-30 23:59:00 ]========
2023-12/export.out:2024-10-15 17:25:42,472 [INFO] export_timeseries.py: ========[ 29 metrics, 1494495 values, oldest @ 1701374401 2023-12-01 00:00:01, newest @ 1704052740 2023-12-31 23:59:00 ]========
2024-01/export.out:2024-10-15 17:27:00,738 [INFO] export_timeseries.py: ========[ 30 metrics, 1261557 values, oldest @ 1704052800 2024-01-01 00:00:00, newest @ 1706731141 2024-01-31 23:59:01 ]========
2024-02/export.out:2024-10-15 17:28:54,672 [INFO] export_timeseries.py: ========[ 30 metrics, 834969 values, oldest @ 1706731200 2024-02-01 00:00:00, newest @ 1709236741 2024-02-29 23:59:01 ]========
2024-03/export.out:2024-10-15 17:30:14,342 [INFO] export_timeseries.py: ========[ 30 metrics, 1214853 values, oldest @ 1709236800 2024-03-01 00:00:00, newest @ 1711915140 2024-03-31 23:59:00 ]========
2024-04/export.out:2024-10-15 17:31:16,346 [INFO] export_timeseries.py: ========[ 29 metrics, 1437306 values, oldest @ 1711915200 2024-04-01 00:00:00, newest @ 1714507141 2024-04-30 23:59:01 ]========
2024-05/export.out:2024-10-15 17:32:32,869 [INFO] export_timeseries.py: ========[ 29 metrics, 1483783 values, oldest @ 1714507200 2024-05-01 00:00:00, newest @ 1717185541 2024-05-31 23:59:01 ]========
2024-06/export.out:2024-10-15 17:33:25,777 [INFO] export_timeseries.py: ========[ 31 metrics, 532012 values, oldest @ 1717185600 2024-06-01 00:00:00, newest @ 1719777540 2024-06-30 23:59:00 ]========
2024-07/export.out:2024-10-15 17:35:04,258 [INFO] export_timeseries.py: ========[ 31 metrics, 486524 values, oldest @ 1719777600 2024-07-01 00:00:00, newest @ 1722455940 2024-07-31 23:59:00 ]========
2024-08/export.out:2024-10-15 17:36:11,679 [INFO] export_timeseries.py: ========[ 30 metrics, 490345 values, oldest @ 1722456000 2024-08-01 00:00:00, newest @ 1725134340 2024-08-31 23:59:00 ]========
2024-09/export.out:2024-10-15 17:36:59,481 [INFO] export_timeseries.py: ========[ 30 metrics, 481736 values, oldest @ 1725134400 2024-09-01 00:00:00, newest @ 1727726340 2024-09-30 23:59:00 ]========

vs filtered sets:

2023-11/export.out:2024-10-15 19:26:30,850 [INFO] export_timeseries.py: ========[ 36 metrics, 460609 values, oldest @ 1698929928 2023-11-02 16:58:48, newest @ 1701374340 2023-11-30 23:59:00 ]========
2023-12/export.out:2024-10-15 19:27:53,125 [INFO] export_timeseries.py: ========[ 29 metrics, 508032 values, oldest @ 1701374401 2023-12-01 00:00:01, newest @ 1704052740 2023-12-31 23:59:00 ]========
2024-01/export.out:2024-10-15 19:28:26,852 [INFO] export_timeseries.py: ========[ 30 metrics, 502793 values, oldest @ 1704052800 2024-01-01 00:00:00, newest @ 1706731141 2024-01-31 23:59:01 ]========
2024-02/export.out:2024-10-15 19:29:22,498 [INFO] export_timeseries.py: ========[ 30 metrics, 473055 values, oldest @ 1706731200 2024-02-01 00:00:00, newest @ 1709236741 2024-02-29 23:59:01 ]========
2024-03/export.out:2024-10-15 19:30:32,888 [INFO] export_timeseries.py: ========[ 30 metrics, 501935 values, oldest @ 1709236800 2024-03-01 00:00:00, newest @ 1711915140 2024-03-31 23:59:00 ]========
2024-04/export.out:2024-10-15 19:31:29,204 [INFO] export_timeseries.py: ========[ 29 metrics, 483872 values, oldest @ 1711915200 2024-04-01 00:00:00, newest @ 1714507141 2024-04-30 23:59:01 ]========
2024-05/export.out:2024-10-15 19:32:00,079 [INFO] export_timeseries.py: ========[ 29 metrics, 498261 values, oldest @ 1714507200 2024-05-01 00:00:00, newest @ 1717185541 2024-05-31 23:59:01 ]========
2024-06/export.out:2024-10-15 19:32:36,189 [INFO] export_timeseries.py: ========[ 31 metrics, 486113 values, oldest @ 1717185600 2024-06-01 00:00:00, newest @ 1719777540 2024-06-30 23:59:00 ]========
2024-07/export.out:2024-10-15 19:32:56,900 [INFO] export_timeseries.py: ========[ 31 metrics, 486422 values, oldest @ 1719777600 2024-07-01 00:00:00, newest @ 1722455940 2024-07-31 23:59:00 ]========
2024-08/export.out:2024-10-15 19:33:49,521 [INFO] export_timeseries.py: ========[ 30 metrics, 490328 values, oldest @ 1722456000 2024-08-01 00:00:00, newest @ 1725134340 2024-08-31 23:59:00 ]========
2024-09/export.out:2024-10-15 19:34:14,550 [INFO] export_timeseries.py: ========[ 30 metrics, 481736 values, oldest @ 1725134400 2024-09-01 00:00:00, newest @ 1727726340 2024-09-30 23:59:00 ]========

Closes #8.