hydra-server.service: Shut up warning about the terminal size being unknown

Dependencies

• [2] ZYEFL36Q Ported/merged properties from the TUD configuration's hydra-module
• [3] BT6SNXUA Add an option to run the hydra server in debug mode
• [4] J57PR4O3 hydra-module: Allow to specify the listen host.
• [5] KNJ6Y5FZ hydra-module.nix: Use -p instead of HYDRA_PORT
• [6] 7XOH2DGH hydra-module.nix: Give types to options
• [7] EE5RRP3X hydra-module.nix: Make services require hydra-init
• [*] D3MDJONY

Change contents

• replacement in hydra-module.nix at line 215
  [2.1129]→[2.1129:1162](∅→∅)
  − environment = serverEnv;
  [2.1129]

  [2.1162]
  + environment = serverEnv // { COLUMNS = "80"; };