Harden test site build

Summary:
Previously, make test was using installed version of upsection,
with installed version of the templates and components.

So, any modification of package.json was totally ignored running
make test.

Furthermore, it also required root access to perform the installation.

This change allows to inject our repository version of everything
for that test site build.

Test Plan:

• edit components/package-template.json
• make test
• check tests/site/package.json matches

Reviewers: MoustaphaAs

Reviewed By: MoustaphaAs

Differential Revision: https://devcentral.nasqueron.org/D3581