Remove redundant configs

Summary:
The dev and prod config files do not differ in any way. Maintaining them separately
puts an unnecessary burden on devs with no upside. If we need this later, we can always revert
this patch.

Test Plan:
Verify various build methods still work as expected:

make container
make run
make serve

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D6589