TASK: WIP Prepare for synchronous content repository

In preparation for https://github.com/neos/neos-development-collection/pull/4988 this will adjust the cr to be synchronous already via a hack and adds a slim b/c block layer which will be removed with the next beta to ease migration.

Upgrade instructions

The CommandResult::block calls must be removed as the backwards compatibility layer will be removed with next beta.

- $contentRepository->handle($command)->block();
+ $contentRepository->handle($command);

Review instructions

Checklist

[ ] Code follows the PSR-2 coding style
[ ] Tests have been created, run and adjusted as needed
[ ] The PR is created against the lowest maintained branch
[ ] Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
[ ] Reviewer - The first section explains the change briefly for change-logs
[ ] Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions

neos / neos-development-collection