Modernize Install

[fernandohds564]

This PR modernizes the installation of mathphys, according to what was discussed in lnls-sirius/scripts#180.

I also removed the use of pkg_resources, since it was also deprecated.

I also removed the import of trackcpp in setup.py to check if it is installed. For two reasons:

• this kind of checking is generally delegated to the builder, via the dependencies argument.
• by default, modern versions of pip builds de package in a separate environment, that does not have trackcpp installed, raising an error when the setup.py module is imported. I don't know which version of pip adopted this behavior, but it used to work on our versions from python3.6. In order to circumvent this error, we would have to call pip --no-build-isolation in our Makefile. I decided go modernize/standardize this behavior to keep things simple and close to the default behavior.