Metadata duration formatting

[fdocr]

Describe the bug The metadata sent in a notifier sends times above 60s with incorrect format.

To Reproduce Steps to reproduce the behavior:

1. Backup a DB in a way it will take more than 60s to dump (0.75GB gzipped backup worked for me)
2. Check notifier metadata (i.e. Slack notifier)

Sample config file

Expected behavior A format similar to 0h 21m 11s

Environment Please complete the following information

• OS: Ubuntu 19.04
• Ruby Version: ruby 2.6.5p114 (2019-10-01 revision 67812) [x86_64-linux]
• RVM/rbenv Version: rvm 1.29.9 (manual) by Michal Papis, Piotr Kuczynski, Wayne E. Seguin [https://rvm.io]

Additional context This might have something to do with rounding float numbers (round up/down as needed) in the lib/martilla/utilities.rb methods.