Incremental improvements of workspace detail view

This is part of #557.

The blueprint says:

the /<scope>/<workspace>/ page is extended to show figures about workflows. It has a list of workflow templates along with count of:

• running workflows
• workflows that need user input
• completed workflows

Each of these figures link back to the list of workflows with the corresponding filters applied.

Also, there is an existing complaint that viewing by default the full JSON description of each work request template can make the page unwieldy as soon as there are nontrivial WorkflowTemplates.

Things to do:

• Redesign the WorkflowTemplate list in the page to now show the WorkflowTemplate definition by default (possibly split it to a new page?)
• Add statistics