Use a project/module-agnostic name for dump files

[fzhinkin]

Currently, dump files are named after a corresponding project. For example, given a project named sample-project, dump files will be:

• sample-project.api for JVM dump;
• sample-project.klib.api for KLib dump.

The project name itself has nothing to do with binary compatibility. And as it was shown in #76 and #231, renaming a project leads to unnecessary troubles.

Switching to a scheme where dumps have fixed (and optionally configurable) names, like jvm.api / klib.api should be considered.