Reana-job-controller

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- Adds support for specifying ``kubernetes_job_timeout`` for Kubernetes compute backend jobs.
- Adds a new condition to allow processing jobs in case of receiving multiple failed events when job containers are not in a running state.

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- Adds database connection closure after each REST API request.
- Adds labels to job and run-batch pods to reduce k8s events to listen to for ``job-monitor``.
- Fixes auto-mounting of Kubernetes API token inside user jobs by disabling it.
- Changes job dispatching to use only job-specific node labels.
- Changes to PostgreSQL 12.8

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- Changes HTCondor to 8.9.11.
- Changes myschedd package and configuration to latest versions.
- Fixes job command formatting bug for CWL workflows on HTCondor.

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- Adds configuration environment variable to set job memory limits for the Kubernetes compute backend (``REANA_KUBERNETES_JOBS_MEMORY_LIMIT``).
- Fixes Kubernetes job log capture to include information about failures caused by external factors such as OOMKilled.
- Adds support for specifying ``kubernetes_memory_limit`` for Kubernetes compute backend jobs.

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- Adds new configuration to toggle Kubernetes user jobs clean up.
- Fixes HTCondor Docker networking and machine version requirement setup.
- Fixes HTCondor logs and workspace files retrieval on job failure.
- Fixes Slurm job submission providing the correct shell environment to run Singularity.
- Changes HTCondor myschedd to the latest version.
- Changes job status ``succeeded`` to ``finished`` to use central REANA nomenclature.
- Changes how to deserialise job commands using central REANA-Commons deserialiser function.

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- Fixes minor code warnings.
- Changes CI system to include Python flake8 and Dockerfile hadolint checkers.