Rename index patterns to improve the readability of the data

[canasdiaz]

Sooner than later we should stop and rethink the naming conventions of the indexes patterns being shown in the dashboard. It is really hard to understand for the users. Some examples:

• github_issues index pattern stores documents both for PRs and issues.
• github2_issues includes documents for the comments and the creation of issues.

Please rename the index patterns so their names are not counterintuitive.