Add Ephemeral storage requests for Nextcloud deployments

[pmig]

Nextcloud seems to write some data into ephemeral storage which is limited by default and exits with following error message:

The node had condition: [DiskPressure].

TerminationByKubelet
The node was low on resource: ephemeral-storage. Threshold quantity: 3092673454, available: 2776124Ki. Container nextcloud was using 1600936Ki, request is 0, has larger consumption of ephemeral-storage. Container nginx was using 1632Ki, request is 0, has larger consumption of ephemeral-storage.