Easy setup&teardown: in-memory or temp data folder

[SebastienGllmt]

Right now in your dolos config you need to choose a path folder

example

[storage]
path = "data"
max_wal_history = 10000

However, when I'm running Dolos on a temporary localhost Cardano chain that deletes itself as soon as I press ctrl+c, I don't want a data folder to stick around since it can cause issues if it's not deleted

There are two ways to solve this imo:

1. easier: add a way to have the storage path be in a temporary OS folder. This option requires little code change on the Dolos side (just fetch the temporary folder path depending on the OS)
2. more complicated: add some switch in the code to use a virtual filesystem or keep things in-memory as an option. This is more complicated because it requires the entire Dolos codebase to be aware that things may be in-memory instead of on disk

Note: as a temporary workaround, you can run

rm -rf ./data && rm -rf dolos.socket && dolos bootstrap relay && dolos daemon

note: rm -f dolos.socket is required because of #293