Enables Configuration Cache for Dokka's build configuration.

Summary

• Enabled CC.
• Set CC error level to 'warn'. (Future build script or plugin changes might cause CC issues. Although such problems should be fixed, I'd rather that developers aren't blocked with CC errors.)
• Updated some build script config to avoid CC issues
  • update usages of project version, to avoid Task.getProject()
  • move variables into gradleEnterprise {} block, to avoid references to the build script context
• Disabled CC for remote Maven publishing tasks. Remote Maven Repos (particularly Maven Central) struggle to cope with parallel uploads, and artifacts may be lost, or split. To prevent issues, CC is manually disabled for all publishing tasks.
• Removed --no-daemon from TeamCity Gradle Steps. TeamCity will instead launch Gradle using the Tooling API (TAPI). (internal discussion).