feat(diagnostics): Add frontend for thread dumps

[Josh-Matsuoka]

Related to cryostatio/cryostat#135

Adds an initial frontend for triggering and displaying thread dumps in cryostat. This is done via a new button on the Diagnostics card which changes to a redirect to the diagnostics page once complete, as well as a new diagnostics page with a table for displaying and downloading captured thread dumps.

To test,

• check out and build the agent PR (feat(diagnostics): Add thread dump capturing to diagnostics endpoint cryostat-agent#639)
• Build the quarkus-agent test application with the above version of the cryostat agent
  -- TAGS=latest ARCHS=amd64 CRYOSTAT_AGENT_VERSION=0.6.0-SNAPSHOT ./build.bash
• check out and build the main cryostat PR (feat(diagnostics): Add thread dumps endpoint and storage cryostat#894)
• deploy everything via smoketest

Opening as draft for now pending a few fixes/adjustments to the backend.