Add ability to set timeline pan mode via config.

tests/config/types.test.ts

@@ -91,6 +91,7 @@ describe('config defaults', () => {
             clustering_threshold: 3,
             events_media_type: 'all',
             mode: 'none',
+            pan_mode: 'pan',
             show_recordings: true,
             style: 'ribbon',
             window_seconds: 3600,
@@ -147,6 +148,7 @@ describe('config defaults', () => {
             clustering_threshold: 3,
             events_media_type: 'all',
             mode: 'none',
+            pan_mode: 'pan',
             show_recordings: true,
             style: 'ribbon',
             window_seconds: 3600,
@@ -271,6 +273,7 @@ describe('config defaults', () => {
           },
         },
         events_media_type: 'all',
+        pan_mode: 'pan',
         show_recordings: true,
         style: 'stack',
         window_seconds: 3600,