feat(environment): add package->application-environment for single-app environments

fix(environment): actually support rename-=unction for renaming binaries

feat: Replace original paths in extra files with the ones in environment

This is for example usable for share/application desktop files, to
point to the environment binary instead of the original binary.
Then the program will be started with environment from the environment
package.

feat: add make-interpreted-environment

Add easy way for creating an environment with an interpterer,
and expose make-python-environment and make-guile-environment

feat: Add make-environment

A procedure to make a package that encapsulates a profile.
This is to stop the propagation of propagated-inputs into a profile.
As an example, multiple python library versions can be used like this
inside of one profile, where each python library version is
encapsulated in a separate environment.