elastic#12242 introduced a unique id for an assignment of shard to a node. We should use these id's to drive the decisions made by IndicesClusterStateService when processing the new cluster state sent by the master. If the local shard has a different allocation id than the new cluster state, the shard will be removed and a new one will be created. This fixes a couple of subtle bugs,  most notably a node previously got confused if an incoming cluster state had a newly allocated shard in the initializing state and the local copy was started (which can happen if cluster state updates are bulk processed). In that case, the node have previously re-used the local copy instead of initializing a new one.

 Also, as set of utility methods was introduced on ShardRouting to do various types of matching with other shard routings, giving control about what exactly should be matched (same shard id, same allocation id, all but version and shard info etc.). This is useful here, but also prepares the grounds for the change needed in elastic#12387 (making ShardRouting.equals be strict and perform exact equality).