The new CSV report was more configurable and could work on proposals,
processes and comments. However, it had several issues.
In the public area, by default it generated a blank file.
In the admin section, the report was hard to configure and it generated
a file with less quality than the old system.
So until we improve this system, we're bringing back the old investment
CSV exporter.
This commit reverts most of commit 9d1ca3bf.
