Add IPFS/Kubo as a Service

[martenwallewein]

revist this implementation and extract the key points: https://github.com/netsys-lab/seed-emulator/tree/leon/ipfs-testbed

[amdfxlucas]

some findings so far:

seedemu/services/Libp2pBwtestService.py

• each server(IPFS instance) container has a separate Go & git installation on its own, checks out and builds the SCION-IPFS fork by itself
  [ -> Nx fold duplication and only indirect sharing through docker build cache (if at all ?!) Has no implications at runtime but still is pain. (increased image size and build time)]

• same here: seedemu/services/ScionKuboService.py

A remedy would be a shared volume containing the build, which is simply mounted into all host-containers (see seed-labs#172) The build itself could be performed once at compile time with a BuildTimeDockerImage like here #1

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ScionKuboService(Service) is a 'Layer' and once #5 is done, should expose the following Options (which can then have different values on each node and also be changed at runtime / without any image rebuilds !! ):

• Swarm.Transports.Network
• Swarm.ResourceMgr.Enabled
• Internal.Bitswap.TaskWorkerCount
• Internal.Bitswap.EngineTaskWorkerCount
• Internal.Bitswap.EngineBlockstoreWorkerCount
• Internal.Bitswap.MaxOutstandingBytesPerPeer
• ... any others ?!

I think this would probably benefit from: #44

didn't look at the testbed itself yet