Feature request: provide project-name placeholder (e.g. `%p`) at project-type definitions

[pataquets]

I'm trying to define a new project type using projectile-register-project-type.
However, I would like to define :compile as docker build -t [project-name] . instead of a fixed string.
I've seen %s replaced by project root in :configure. It would be great having something like %p which would expand to projectile-project-name.

[bbatsov]

Most of those settings are just strings that we don't post-process. It will be relatively easy to do something like this - e.g. if there's some string you replace it with the project root. If someone wants to work on this - I'll accept a PR. As most build tools operate on the current folder I don't see much value in this in general, and it's low prio for me.