[BlobDB] Move timer queue based tasks to repeatable threads

[sagar0]

Switch to using RepeatableThread in BlobDB instead of TimerQueue.

• We were using TimerQueue in BlobDB to run tasks at fixed intervals. With the introduction of RepeatableThread, we no longer need to rely on TimerQueue code.
• Remove all reference to TimerQueue.

Test Plan:
Run all tests using make check. Test with clang as well using: USE_CLANG=1 make all

[facebook-github-bot]

@sagar0 has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[facebook-github-bot]

@sagar0 has updated the pull request. Re-import the pull request

[facebook-github-bot]

Hi @sagar0!

Thank you for your pull request.

We require contributors to sign our Contributor License Agreement, and yours needs attention.

You currently have a record in our system, but the CLA is no longer valid, and will need to be resubmitted.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[cscetbon]

did we lose @sagar0 ?