feat(diagnostics): Add endpoint for triggering heap dumps

[Josh-Matsuoka]

Fixes cryostatio/cryostat#134

Adds agent support for interacting with the heap dumps system. This allows you to trigger and retrieve heap dumps from a target with the agent enabled. This is done through the mbean-invoke endpoint and the HotspotDiagnosticMBean to create the heap dump, then a similar mechanism to the recording harvester that pushes the heap dump to the server through the heapdump/upload endpoint.

To test:

Setup

• Check out this PR, as well as feat(diagnostics): Add frontend for heap dumps cryostat-web#1730 and feat(diagnostics): Add endpoints and storage handling for heap dumps cryostat#984
• Build all 3, build the quarkus-agent sample application with the PR version of the cryostat agent.
• Run smoketest bash smoketest.bash -O -t quarkus-cryostat-agent
• Open the Web UI and test the functionality
• Check the smoketest logs to make sure the agent receives the requests and doesn't throw any errors.

Diagnostics Card

• Check that the Heap Dumps button appears on the diagnostics card.
• Verify that clicking the Invoke Heap Dumps button triggers 2 notifications, one for a successful invocation (Heap Dump Success), and one for a successful upload to the server (Heap Dump Uploaded)
• Verify that the redirect button becomes enabled and takes you to the Heap Dumps table

Capture Diagnostics Page

• Check that the Heap Dumps button appears on the capture diagnostics page.
• Verify that clicking the Invoke Heap Dumps button triggers 2 notifications, one for a successful invocation (Heap Dump Success), and one for a successful upload to the server (Heap Dump Uploaded)
• Verify that the redirect button becomes enabled and takes you to the Heap Dumps table

Heap Dumps Table

• Check that the earlier triggered heap dumps appear in the table with a name, last modified time, and file size that makes sense
• Verify that each table entry has a dropdown for downloading and deleting the heap dump.
• Verify that heap dumps can be downloaded and deleted.
• Verify that deleting a heap dump produces a notification (Heap Dump Deleted) and refreshes the table