MBeans tab: Make ATTRIBUTE and OPERATION MBean tree nodes "live"

When an attribute or operation node in the MBean tree is selected (e.g. getVMOption),
the proposed design is to show the UI for that particular attribute/operation. For
example, the "getVMOption" button with the text fields for input parameters.

Make ATTRIBUTE nodes live:
- Display under Attributes each attribute individually with its value and its metadata.

Make OPERATION nodes live:
- Display under Operations each operation individually with its operation input text
  fields plus invocation button and its metadata and its parameters and metadata.