Customize darkbot build process

Summary:
The build.sh script shipped with with the repository
contains an install step. This install step overwrites
existing configuration files. So, we discard it.

Ref T1129.

Test Plan: Check /opt/odderon/darkbot isn't populated by make install

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1129

Differential Revision: https://devcentral.nasqueron.org/D863