Add a configuration option to show absolute dates next to builds

Problem Definition

When we look at the build dashboard, we see some relative dates like below instead of showing the absolute dates. It is challenging to find the actual date by hovering the mouse over the relative date to know the actual build date. 

Suggested Solution

Introduce a JVM argument to toggle this behaviour. For instance, something like adding '-Datlassian.bamboo.build.showabsolutedates=true' to JVM argument should display absolute value in the dashboard and in other places where the relative date values are stored.

Why this is important

When we have a lot of builds in the dashboard and when Bamboo displays like '1 month ago' or so, it gets challenging to get a gist of the exact date.

Workaround

Hover the mouse over the relative date and we see the absolute value.