Refactor out translation.h
Summary:
This is a prerequisite for introducing bilingual error messages.
Note: #includes are arranged by clang-format-diff.py script.
Some weird stuff are going on in the seeder tests, so decision had to be made.
This is a partial backport of Core PR16362 : https://github.com/bitcoin/bitcoin/pull/16362/commits/0b86e517ad733c8740c519332aa4c0e9035dbaab
Test Plan:
ninja all check-all
Reviewers: #bitcoin_abc, Fabien
Reviewed By: #bitcoin_abc, Fabien
Differential Revision: https://reviews.bitcoinabc.org/D6048