Make libmariadb-dev breaks/replaces libmysqlclient-dev (Closes: #863675)

This mimics how libmariadbclient-dev used to breaks/replaces the same
libmysqlclient-dev package. These packages are not supposed to be
co-installable anyway.

Among others, the following files conflict:
- /usr/bin/mysql_config
- libmysqlservices.a
- mysql.m4

Also, wrap-and-sort -a in this commit.