Consolidate File I/O usage

We use file access at several places (Read files, write files, ...). We should find all that places and create a solid facade for it (in swirlds-common).

# Step 1
Find all the places and create a good overview

# Step 2
Define how the architecture (maybe a facade) will look like in future

# Step 3
Migrate current code

Start by surveying the existing file-access locations described in the issue and record them in an overview. Then examine swirlds-common and define the proposed facade architecture before planning migration of the current code. Done means the overview, architecture, and migrated usages are complete.

Written by the indexing model from the issue text.