[k8s] Add configurable master pod timeout to Kubernetes backend

[bystepii]

This pull request introduces a new configurable parameter, master_timeout, to the Kubernetes backend.

Motivation

There may be jobs that last more than 10 minutes, which is the default master pod duration. Although the master pod is expected to restart automatically, there are cases where it does not restart or after restarting some jobs are lost, resulting in jobs shown in Lithops logs as Pending.

The new master_timeout parameter mitigates these issues by allowing to configure a suitable timeout based on the job requirements.

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[JosepSampe]

Looks good, thanks @bystepii!

[kikemolina3]

Great contribution! Thank you @bystepii