wavehunter: add QMDL storage

Instead of reading/writing to a single QMDL file, we now can manage
a directory of several files, and have the ability to start/stop writing
to them on the fly.

This commit also adds graceful exiting to the server, so we can perform
cleanup steps when the server's exiting.

wavehunter/static/css/style.css

@@ -0,0 +1,40 @@
+td,
+th {
+  border: 1px solid rgb(190, 190, 190);
+  padding: 10px;
+}
+
+td {
+  text-align: center;
+}
+
+tr:nth-child(even) {
+  background-color: #eee;
+}
+
+th[scope='col'] {
+  background-color: #696969;
+  color: #fff;
+}
+
+th[scope='row'] {
+  background-color: #d7d9f2;
+}
+
+tr.current {
+  background-color: #fe537b;
+  font-weight: bold;
+}
+
+caption {
+  padding: 10px;
+  caption-side: bottom;
+}
+
+table {
+  border-collapse: collapse;
+  border: 2px solid rgb(200, 200, 200);
+  letter-spacing: 1px;
+  font-family: sans-serif;
+  font-size: 0.8rem;
+}