filodb(core) include the start time for range functions such as rate.

[yu-shipit]

Pull Request checklist

• The commit(s) message(s) follows the contribution guidelines ?
• Tests for the changes have been added (for bug fixes / features) ?
• Docs have been added / updated (for bug fixes / features) ?

Current behavior : (link exiting issues here : https://help.github.com/articles/basic-writing-and-formatting-syntax/#referencing-issues-and-pull-requests)

New behavior :

The result of a range vector function is based on the data in a range. Previous the first millisecond of data was excluded from the range, now it is included. Let's say, we have a ts counter { [0s, 1.0], [5s, 6], [10s, 16].

Previously, rate(count)[10s] at timestamp 10 just has two data points [5s, 6] and [10s, 16] it may result in a result (16 - 6) /5 =2.

Now, the [0s, 1.0] is included so, the rate would be (16 - 1) / 10 = 1.5

After this change, Filodb will be compliant to Prometheus.
BREAKING CHANGES

Breaking changes may include:

• Any schema changes to any Cassandra tables
• The serialized format for Dataset and Column (see .toString methods)
• Over the wire formats for Akka messages / case classes
• Changes to the HTTP public API
• Changes to query parsing / PromQL parsing

Other information:

[yu-shipit]

Since we include the start time, we do not need to extend the lookback window anymore.
Here is an example, the window is 15s and no need to extend the window to 15001ms
[2023-09-12 15:47:51,816] INFO query-sched-1 default f.query.Query$ [] - functionId=Some(Rate) stepMultipleNotationUsed=false window=15000 rv=RawDataRangeVector(/shard:3/b2[schema=prom-counter _metric_=my_counter,tags={_ns_: Test-data-1694557937_p1, _ws_: aci-telemetry, code: 817, instance: inst-4, mode: nice, service: service-2, version: 3.3.13}] [grp16],TimeSeriesPartition(shard=3,partId=112){b2[schema=prom-counter _metric_=my_counter,tags={_ns_: Test-data-1694557937_p1, _ws_: aci-telemetry, code: 817, instance: inst-4, mode: nice, service: service-2, version: 3.3.13}]},TimeRangeChunkScan(1694557922000,1694557937000),[I@65c327b0,0,200000000,dcd2633e-6b01-4d89-8d73-124b18cacdfd)

[alextheimer]

@yu-shipit Could you include a quick summary of the PR in the header comment?

[alextheimer]

Most changes look good-- just a couple questions. Thanks for the tedious work here @yu-shipit 🙏