Fix bsc#973999
- rabbitmq-server.service: increase NOFILE limit per documentation
- rabbitqm-server.ocf: add OCF_RESKEY_limit_nofile parameter
default as 65535

- rabbitmqctl: clear CMDLINE before appending

- update to 3.5.4:
Runtime I/O thread pool size is now 64 instead of 30 by default.
This reduces time spent waiting for file I/O operations to complete
on machines with 8 or more cores.
* https://github.com/rabbitmq/rabbitmq-server/releases/tag/rabbitmq_v3_5_4

- rabbitmq-server.service: switch to type=Notify in order to
avoid cookie creation race

- update to 3.5.3:
3.5.2 and 3.5.3 are bugfix releases. See:
* https://github.com/rabbitmq/rabbitmq-server/releases/tag/rabbitmq_v3_5_2
* https://github.com/rabbitmq/rabbitmq-server/releases/tag/rabbitmq_v3_5_3