feat(log_store): introduce the CollectionTask (#4530)

* feat: introduce the `CollectionTask`

* feat: add config of index collector

* chore: remove unused code

* feat: truncate indexes

* chore: apply suggestions from CR

* chore: update config examples

* refactor: retrieve latest offset while dumping indexes

* chore: print warn

Cargo.lock

@@ -3170,6 +3170,15 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "delta-encoding"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f8513a5eeb3d7b9149563409dc4ab6fd9de5767fd285af5b4d0ee1b778fbce0"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "der"
 version = "0.5.1"
@@ -5806,10 +5815,12 @@ dependencies = [
  "common-test-util",
  "common-time",
  "common-wal",
+ "delta-encoding",
  "futures",
  "futures-util",
  "itertools 0.10.5",
  "lazy_static",
+ "object-store",
  "pin-project",
  "prometheus",
  "protobuf",