Add Development Environment Setup

[Process-ing]

Description

This PR adds instructions to the README to run the package in a development environment, complementing the current one for Clava-JS.

[joaobispo]

Wondering if we need Clava-JS in development mode, or if we could just use a version in NPM. Was this on purpose?

[Process-ing]

I think that it should be possible. I included this approach because the developer will also probably work with the standard LARA and Clava repositories, but this shouldn't be a limitation. Do you think I should also include a section for working with the NPM packages of Clava-JS?

[joaobispo]

In the best case scenario, this is a standalone library that does not need to change the internals of Clava or LARA. However, this library in particuly might be dependant of Clava's internals, how was your experience developing the library, do you find it useful to have the source code of both Clava and LARA?

[Process-ing]

In my case, I only used the LARA and Clava repositories to get a closer notion of the API, I did not strictly need to change anything in their code. However, I don't think this will be the general case, as most people will probably use the visualization tool when working with the other repositories.
Nonetheless, it can be useful for some that are making other changes for this tool only, so I will try to add this setup option in this guide (if possible).