New segment: support for 'visitConvertedGoalId' in all reports (visitors who converted a particular Goal)

[mattab]

When requesting goal report with particular segment value, got the following error:

Table 'log_conversion', can't be joined for segmentation

Reported in the forums

URL to reproduce

We should support the use case of segment containing 'visitConvertedGoalId' on the Goal/Ecommerce reports.

[mattab]

it was also reported in #4642

[mattab]

In 0003030: Refs #4503 adding test cases showing the missing feature / exception message

[mattab]

In 17d6057: Fixes #4503 visitConvertedGoalId now works in all reports. Note that this also fixes another bug in the Ecommerce items reports!

[mattab]

In 362db0a: Refs #4503 better tests