Upgrade java build

[yuzawa-san]

Issue #, if available: none

Description of changes:

hello kevin, i'm glad we're on github now

• this pr is in preparation for a subsequent pr related to maven publication
• manage version, name, and group in a cleaner manner (e.g. version in gradle.properties). feel free to suggest a different naming scheme
• remove broken dependency to lib
• make it compile on jdk 25, upgrade gradle and various plugins to work on that version
• add rudimentary github actions build job for PR's
• convert enforcedPlatform to platform to work with maven uploads

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[kchiang6997]

Thanks James, the changes look good - as a note we are now officially supported by the IAB, so all PRs should now go to https://github.com/IABTechLab/DynamicTrafficEngine.

[yuzawa-san]

@kchiang6997 thanks, we have migrated the changes over to IABTechLab/DynamicTrafficEngine#7