Use Develocity build cache configuration and access key authentication

[tylerbertrand]

Gradle configuration changes

Update the existing HttpBuildCache remote build cache configuration to develocity.buildCache configuration, enabling access key authentication.

GitHub Actions workflow changes

In the CI GitHub Actions workflow, update the GRADLE_ENTERPRISE_ACCESS_KEY environment variable to the new DEVELOCITY_ACCESS_KEY environment variable, which is the authentication environment variable as of the move from the Gradle Enterprise Gradle plugin to the Develocity Gradle plugin. Also, remove the now-unused GRADLE_ENTERPRISE_CACHE_PASSWORD environment variable.

[eddumelendez]

Thanks for your contribution, @tylerbertrand !