Support Multiple Projects in k6 tests

Closes #105 (closed)

We need to have support for testing multiple Gitaly nodes in HA environments since Gitaly isn't HA itself. To achieve this the tool is being updated to have multiple projects in target environments (each in this case deployed to a separate Gitaly node)

In detail this MR does the following:

• Refactors the tool to accept and use multiple projects in tests (selected at random but in such a way that there's still an even spread)
• Adds in safeguards for each test as it pulls in project info. Each test now passes a list of data keys it expects each project to have. If none found it exits.
• Updates the run-k6 tool reports to be clearer
• Updates import-project to specify specific storage paths to import projects to
• Adds a copyleft license to the tool
• Updates docs on the above