The read-only-allow-delete block is not really under the user's control
since Elasticsearch adds/removes it automatically. This commit removes
support for it from the new API for adding blocks to indices that was
introduced in #58094.
Adds an API for putting an index block in place, which also ensures for write blocks that, once successfully returning to
the user, all shards of the index are properly accounting for the block, for example that all in-flight writes to an index have
been completed after adding the write block.
This API allows coordinating more complex workflows, where it is crucial that an index is no longer receiving writes after
the API completes, useful for example when marking an index as read-only during an upgrade in order to reindex its
documents.
