5.1.5: Fix H2 Java 8 support

• Fix/clarify API running standalone
  • Will now error out and let user know that they shouldn't install the API standalone
• Update Gradle
  • 8.11 -> 8.11.1
• Downgrade H2 from 2.3.232 to 2.2.224
  • 2.3.X requires Java 11+, we need to support Java 8+
• Update Blossom
  • Blossom updated from 1.3.1 to 2.1.0
  • Added gradle-idea-ext-plugin for Blossom
  • Moved ANNOYING_API_VERSION into separate BuildProperties class
  • ANNOYING_API_VERSION is no longer a SemanticVersion, it's now just a regular String
• Update Java version for build processes
  • 8 -> 11
• Bump version (5.1.5)

Full Changelog: 5.1.4...5.1.5