Add global search backfill worker (#7860)

* Add search backfill worker

This will run on background at most once an hour while the device has internet connectivity and the device is charging and start back-paginating through the user's rooms to make sure the search results are populated.

It'll run for the maximum time the default workers allow, 10 minutes.

* Create `RustMatrixClient.Factory` AssistedFactory to help with DI and add `SearchBackfillService`

* Start search backfill when entering the search screen, just once. This should help getting initial search results if none or few are found at first

libraries/matrix/impl/build.gradle.kts

@@ -63,6 +63,7 @@ dependencies {
 
     implementation(projects.appconfig)
     implementation(projects.features.enterprise.api)
+    implementation(projects.features.networkmonitor.api)
     implementation(projects.libraries.androidutils)
     implementation(projects.libraries.architecture)
     implementation(projects.libraries.di)
@@ -80,6 +81,7 @@ dependencies {
 
     testCommonDependencies(libs)
     testImplementation(projects.features.enterprise.test)
+    testImplementation(projects.features.networkmonitor.test)
     testImplementation(projects.libraries.featureflag.test)
     testImplementation(projects.libraries.matrix.test)
     testImplementation(projects.libraries.previewutils)