conf_write() can now remove literal "\n"

#1367

branch: 1367-dev-gab from dev branch

Can heal env files with the following

issue 1

someparameter:43\nanotherparameter:44\n

becomes

someparameter:43
anotherparameter:44

issue 2

someparameter:43\n
anotherparameter:44\n

becomes

someparameter:43
anotherparameter:44