Configure SonarCloud

[hariso]

Description

Configures SonarCloud for Conduit, so that we can get the test coverage displayed and checked in PRs and in our README. I'll add a SonarCloud badge once the PR is merged to main.

Quick checks

• [x] I have followed the Code Guidelines.
• [x] There is no other pull request for the same update/change.
• [ ] I have written unit tests.
• [x] I have made sure that the PR is of reasonable size and can be easily reviewed.