Add information about motivating others

[hectorsector]

Suggestion from @carolynshin:

maybe this is covered in the case study section but i would also want to know - ok i’m excited about innersource, i wanna do this, i’m learning about it but how do i get my colleagues excited about it?

[hectorsector]

I’m not sure if this resource would cover it, but @stoe shared this report from RedHat.

It speaks to motivation, but maybe from the C-level perspective. @carolynshin do you think this resource speaks to the motivation as you imagined it?