Show task duration on tasks page

[shreddedbacon]

Since tasks and deployments both have similar fields, it would be possible to show the duration of a task on the tasks page, similar to how the deployments page lists this.

The tasks query would just need to be extended to include the started and completed fields (https://github.com/uselagoon/lagoon-ui/blob/main/src/lib/query/EnvironmentWithTasks.js#L62-L69)

The tasks page then just needs to be updated with a duration column similar to deployments (https://github.com/uselagoon/lagoon-ui/blob/main/src/components/Deployments/index.tsx#L74)