feat: full refresh (#166)

Description

• reorganize FS configuration
  • create mountpoint configuration structs
• refactor FS pool managers
  • create zfs and lvm filesystem managers
• retrieval pool rotation
  • detect the next pool to update
  • pool switching
  • reload service configuration
• running an actual retrieval chain
  • reproduce retrieval job execution
• running a refresh scheduler
  • create a timetable
  • cancel nested snapshot schedulers
• cloning with different fs pools
  • provide fs managed pools to the cloning service
  • adopt cloning operations
• idle timeouts
  • detect clone idleness for all managed pools

Related issue

#166 (closed)

Examples

global:
  engine: postgres
  debug: true

poolManager:
  mountDir: /var/lib/dblab
  dataSubDir: data
  clonesMountSubDir: clones
  socketSubDir: sockets
  preSnapshotSuffix: "_pre"

provision:
  portPool:
    from: 6001
    to: 6005
  dockerImage: "postgresai/extended-postgres:12"

retrieval:
  refresh:
    timetable: "0 0 * * 1"

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes, specifications reflect those changes and they have been reviewed OR there are no API changes

Closes #166 (closed)