standardize Contributing.md, README.md add AUTHORS.md

Hello,

several md files in schema2ldif are not the same as in tohers project for the common part

we should fix that

Cheers

assigned to @bmortier

added PJ1802-0188 label

changed milestone to %Schema2ldif 1.3.1

closed via commit 5e107190

reopened

added 20m of time spent

closed