The forking facility has been replaced by ForkedChain - frames and
layers are two other mechanisms that mostly do the same thing at the
aristo level, without quite providing the functionality FC needs - this
cleanup will make that integration easier.
Saving both memory and processing, we can move entries from one
savepoint to another, specially when the target is empty as it often is
during transaction processing
`initTable` is obsolete since nim 0.19 and can introduce significant
memory overhead while providing no benefit (since the table will be
grown to the default initial size on first use anyway).
In particular, aristo layers will not necessarily use all tables they
initialize, for exampe when many empty accounts are being created.
