Add more examples to introduction

[librarianlise]

Can we provide some examples in the intro about how different kinds of library folk in different roles and types of libraries use it? So that we have some public, academic, some 'tech services', some 'public services'

https://librarycarpentry.org/lc-sql/01-introduction/index.html

There is a list of examples on that page, but it's not clear how instructors would actually talk about those, as they're pretty broad. Maybe a few specific examples would be more helpful?

[libcce]

@librarianlise as I was familiarizing myself with the lesson again, I found this https://github.com/LibraryCarpentry/lc-sql/blob/gh-pages/_extras/learner_profile.md. Is this what we are aiming for?

[jyssy]

@librarianlise Where would you like these examples to sit in the page? Under 'what is SQL?' or perhaps 'Why are people working in library- and information-related roles well suited to SQL?'

[jyssy]

Currently has 8 examples.