Make dependencies into workspace dependencies.

The once_cell dependency has been removed entirely and replaced
with equivalent types from std.

Relatedly, in ledger/store/src/helpers/rocksdb/internal/mod.rs,
I commuted what was a Mutex<Lazy<..>> into a Lazy<Mutex<..>>, which
was likely the intent.

There were previously many renames of crate dependencies. I've undone
some of these renames, as I think they just make it harder to follow
which crate is which. But some I've kept (now done by
`extern original_name as new_name` as workspace dependencies can't
be renamed in the other way), largely just to avoid having an even
larger diff.

Author: mikebenfield