Provide a progress indicator on CockroachDB Debug Tsdump

**Is your feature request related to a problem? Please describe.**
Today, when uploading to datadog, the script just outputs chunks of 100 metrics at a time. However, depending on the size of the tsdump, you don't know when it'll finish.

The challenge is when you have to leave your desk, and the upload takes a while, you can't let your machine go to sleep.

**Describe the solution you'd like**
Provide a progress indicator periodically. so users can get an estimate on how long it will take to upload.

**Additional context**

@arjunmahishi noted the following:

> I remember this was the initial idea. But calculating the progress in % while concurrently uploading chunks (without taking a performance hit) was proving to be really tricky. So, we didn't end up implementing it. I do agree that it would be a better UX.

Jira issue: CRDB-50383

Epic CRDB-52093