HDDS-7141. Recon: Improve Disk Usage Page

[smitajoshi12]

What changes were proposed in this pull request?

1. Make the DU page's texts the same font and color as on the other pages in Recon.
2. The chart description (which color stands for which volume/bucket/key) could be a bit bigger
3. If we click into the chart parts we go into that bucket and change the pie chart accordingly. If we click on the last key there is no pie chart showing up, we could change this to show a pie chart with 100% of the key.
4. There is a button on the right side that says Show Metadata for Current Path. If we click on it there is a page popping up on the right side with information about the current path. We could fix this page on the right side as we have plenty of space to do that. We can remove the button in this case and we don't need to make the left side of the page (the chart) grey.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-7141

How was this patch tested?

Manually

[adoroszlai]

Whoever merges this, please make sure to edit the commit message to match PR title if necessary (because GitHub uses the message from commit by default if the PR has a single one).

[adoroszlai]

@dombizita @smengcl please review

[kaijchen]

Whoever merges this, please make sure to edit the commit message to match PR title if necessary (because GitHub uses the message from commit by default if the PR has a single one).

This could be changed in repo settings under "General - Pull Requests". However, it has to be done by the infra team.

[smengcl]

The Disk Usage page is throwing errors when the cluster is empty on my side. @smitajoshi12 Would you check if this is the case on your docker cluster (when empty) as well?