The docker local copies of DB initialization scripts were out of sync
with the master copies. Instead of updating local copies, adjust docker
compose to reference master copies directly.
Also change docker config to use docker volumes instead of mounted
directories for all DB data.
Reasons:
- Riak DB development is almost halted after Basho
- riak-erlang-client is abandoned and doesn't work
correctly with OTP22
- Riak is slow in comparison to other databases
- Missing key ordering makes it impossible to implement range
queries efficiently (e.g. MAM queries)
