Adds definition of repository in Rakudo/Perl 6 context
Adds definition of repository in Rakudo/Perl 6 context

This is ripped of off @jnhtn's
https://github.com/rakudo/rakudo/blob/master/docs/module_management.md
with the idea of contributing towards #502 (TTBOMK, of course).

tbrowder/doc,stmuk/doc,jonathanstowe/doc,MasterDuke17/doc,perl6/doc,MasterDuke17/doc,dmaestro/doc,jonathanstowe/doc,stmuk/doc,dmaestro/doc,jonathanstowe/doc,perl6/doc,perl6/doc,tbrowder/doc,perl6/doc,stmuk/doc,MasterDuke17/doc,stmuk/doc,dmaestro/doc,tbrowder/doc,MasterDuke17/doc,jonathanstowe/doc,dmaestro/doc,stmuk/doc,jonathanstowe/doc,dmaestro/doc,tbrowder/doc,perl6/doc