Ensure that rebar exists and his version is correct

Currently, we relay on the fact that rebar is installed somehow in the system before user runs ./configure. This causes the following issues:

• rebar may actually not being available
• rebar version may be too old

To avoid these issues and make install process more "relaxed", on ./configure phare we could build rebar before fetch any dependencies. Hopefully, we have own fork to not depend on remote upstream.

However, it's not wise to always build our own rebar on ./configure - on the end user system there could be already installed rebar with the right version. For this case, we need to provide a switch flag like --with-system-rebar for ./configure script which check if the system rebar version is correct (iirc, we need 2.3.1+, but need to double check that).