HDDS-7692. Remove usage of MonotonicClock as default Clock used

[siddhantsangwan]

What changes were proposed in this pull request?

From the jira:

Similar to HDDS-7463, we are seeing that commands sent from SCM to the datanodes are being expired when they should not be. This is because we are getting the command deadline from MonotonicClock and then comparing that with the current time, also gotten from MonotonicClock on the datanodes.
As we discovered in HDDS-7463, the "Time" monotonic clock uses is not system time, but some arbitrary reference point in the JVM. We cannot use the time from monotonic clock to compare times across JVM restarts, or in different JVMs.
For that reason, I believe it would be safer to replace any usages of Monotonic clock with java.util.SystemClock.

This PR replaces usages of MonotonicClock with SystemClock from Clock in the java.time package.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-7692

[sodonnel]

LGTM. I believe we need to remove the usage of the MonotonicClock as its caused a few problems, and the only alternative I can think of is to use the System clock instead.