fix: Support longer runner image build timeouts

[kichik]

Support setting longer timeouts for image runner builds. Previously we used custom resources that are limited to 1 hour. Now we will use a wait handle with support for up to 8 hours (the maximum CodeBuild supports). We now also confirm the requested timeout is supported and fail early if it doesn't.

This doesn't affect:

• AMI builds
• Windows Docker image builds
• Explicit AWS Image Builder builds (builderType: RunnerImageBuilderType.AWS_IMAGE_BUILDER)

Don't forget to set the builder timeout with:

const fargateX64Builder = FargateRunnerProvider.imageBuilder(stack, 'Fargate builder', {
  codeBuildOptions: {
    timeout: cdk.Duration.hours(8), // 8 hours is the max supported by CodeBuild
  },
});

Fixes #540