RFR: 8103: Add user configuration for local JVM refresh interval

[Marcus Hirt]

On Thu, 20 Jul 2023 13:56:07 GMT, Alex Macdonald <aptmac at openjdk.org> wrote:

> This PR addresses JMC-8103 [[0]](https://bugs.openjdk.org/browse/JMC-8103), in which it would be nice to have a user control for adjusting the rate at which the JVM browser discovers JVMs.
> 
> At the moment, the `LocalDescriptorProvider` scans every 5s for differences in local JVMs, and then goes through the process of creating a local descriptor, attaching, populating the jvm browser, etc.
> 
> This PR adds an extra field to the Preferences under `Preferences -> JVM Browser -> Local` that lets the user specify how frequently (or infrequently) this scan should occur. As mentioned at the latest upstream community meeting, this value should probably have a lower-bound as to not scan too often, so I've selected 1000 ms to match similar refresh rates of the jvm browser.
> 
> ![example](https://github.com/openjdk/jmc/assets/10425301/4dbe363f-a3d4-4513-9654-f99cfe71aaeb)
> 
> 
> [0] https://bugs.openjdk.org/browse/JMC-8103

Marked as reviewed by hirt (Lead).

Thanks for the contribution Alex! :)

-------------

PR Review: https://git.openjdk.org/jmc/pull/508#pullrequestreview-1541900778
PR Comment: https://git.openjdk.org/jmc/pull/508#issuecomment-1646295145