Fixed bug with first execution of K8s and Singularity

[macarronesc]

When a run was launched with the work queue system and the workers were not started yet, they never received the task.

This commit fixes this bug by making the RabbitMQ queue durable.

Additionally, lithops clean has been improved for these backends.

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[JosepSampe]

Thanks @macarronesc , can you fix linting?

[macarronesc]

Done!