feat: add wget support

[danielefranceschi]

This PR mainly adds support for using wget instead of being locked on curl.

Why?

Because I personally prefer wget.

Detailed changes

• abstracted the network calls so that it detects if curl is present, or we shall use wget
• all bats tests updated mocking wget as well
• added wget and PAT support also in install.sh
• added integration tests with real installation, both in alpine (with wget) and debian

[marverix]

@danielefranceschi Wow! Very nice! I love the abstract http_get and http_download! Thanks!

[marverix]

@all-contributors please add @danielefranceschi for code

[allcontributors]

@marverix

I've put up a pull request to add @danielefranceschi! 🎉