Add ability to read data from time series

gen_dataset() first reads time series from campaign, then reads any additional
data from history files (from archive or run directory). There's an API change
where, instead of expecting start_date and end_date (strings formatted as
'YYYY-MM'), the function wants integers start_year and end_year. Figuring out
better default values will be necessary to extend this to other CESM runs but
it's a good start.

I split plot_suite_004.ipynb into 4-year segments, as it was choking on 8 years
of output. I also added plot_suite_map notebooks for 004 for years 0006 and
0007 (we're one month shy of 0008).

notebooks/Sanity Check.ipynb

@@ -30,10 +30,10 @@
       "Last average written at 0001-04-25 00:00:00\n",
       "Datasets contain a total of 124 time samples\n",
       "Last average written at 0001-05-05 00:00:00\n",
-      "Datasets contain a total of 151 time samples\n",
-      "Last average written at 0001-06-01 00:00:00\n",
-      "Datasets contain a total of 151 time samples\n",
-      "Last average written at 0001-06-01 00:00:00\n"
+      "Datasets contain a total of 365 time samples\n",
+      "Last average written at 0002-01-01 00:00:00\n",
+      "Datasets contain a total of 365 time samples\n",
+      "Last average written at 0002-01-01 00:00:00\n"
      ]
     }
    ],
@@ -58,13 +58,17 @@
     ")\n",
     "\n",
     "cases[\"003\"] = utils.CaseClass(\"g.e22.G1850ECO_JRA_HR.TL319_t13.003\")\n",
-    "ds_dict[\"003\"] = cases[\"003\"].gen_dataset(\n",
-    "    stream=\"pop.h.nday1\", varnames=varnames, end_date=\"0001-05\"\n",
+    "ds_dict[\"003\"] = (\n",
+    "    cases[\"003\"]\n",
+    "    .gen_dataset(stream=\"pop.h.nday1\", varnames=varnames, end_year=1)\n",
+    "    .isel(time=slice(0, 151))\n",
     ")\n",
     "\n",
     "cases[\"004\"] = utils.CaseClass(\"g.e22.G1850ECO_JRA_HR.TL319_t13.004\")\n",
-    "ds_dict[\"004\"] = cases[\"004\"].gen_dataset(\n",
-    "    stream=\"pop.h.nday1\", varnames=varnames, end_date=\"0001-05\"\n",
+    "ds_dict[\"004\"] = (\n",
+    "    cases[\"004\"]\n",
+    "    .gen_dataset(stream=\"pop.h.nday1\", varnames=varnames, end_year=1)\n",
+    "    .isel(time=slice(0, 151))\n",
     ")"
    ]
   },

notebooks/plot_suite_003.ipynb

@@ -56,7 +56,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "dashboard_link=https://jupyterhub.ucar.edu/dav/user/mlevy/proxy/39042/status\n"
+      "dashboard_link=https://jupyterhub.ucar.edu/dav/user/mlevy/proxy/41634/status\n"
      ]
     },
     {