feat(process): redo bootstrap after X amount of time

fixes #20

In the 'watch' step, I get the state after each iteration, then if now - last time bootstrap was done is more than the time to redo the bootstrap, the settings

```js
stateManager.set({
  seq: 0,
  bootstrapDone: false,
});
```

are being set, which *should* make the bootstrap start over.

config.js

@@ -8,6 +8,7 @@ const defaultConfig = {
   indexName: 'npm-search',
   replicateConcurrency: 10,
   bootstrapConcurrency: 100,
+  timeToRedoBootstrap: 604800000 /* one week */,
   seq: null,
   indexSettings: {
     searchableAttributes: [
@@ -20,7 +21,6 @@ const defaultConfig = {
       'owners.name',
     ],
     attributesForFaceting: [
-      'onlyFilter(name)' /* to be removed when frontend concatenates */,
       'onlyFilter(concatenatedName)' /* optionalFacetFilters to boost the name */,
       'keywords',
     ],

index.js

@@ -104,6 +104,7 @@ function bootstrap(state) {
           log.info('⛷ Bootstrap: done');
           return stateManager.save({
             bootstrapDone: true,
+            bootstrapLastDone: new Date().toISOString(),
           });
         }
 
@@ -179,6 +180,17 @@ function watch({ seq }) {
             seq: change.seq,
           })
         )
+        .then(stateManager.get)
+        .then(({ bootstrapLastDone }) => {
+          const now = new Date();
+          const lastBootstrapped = new Date(bootstrapLastDone);
+          if (now - lastBootstrapped > c.timeToRedoBootstrap) {
+            stateManager.set({
+              seq: 0,
+              bootstrapDone: false,
+            });
+          }
+        })
         .catch(reject);
     });
     changes.on('error', reject);