Path to feature file in allure report

[//]: # (
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#### I'm submitting a ...
- [ ] bug report
- [x] feature request
- [ ] support request => Please do not submit support request here, see note at the top of this template.

#### What is the current behavior?

I have tests in many directories (many repos, in fact). All get run together for a report we gen in Allure.
The report shows the feature name. However, there seems to be no way to display the path to the feature file.
Because the tests are in lots of dirs - it is then rather painful to find the right file.

#### If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem

#### What is the expected behavior?

Would love for the plugin to also set the path to feature file in the allure report.

#### What is the motivation / use case for changing the behavior?

Ease of use for developers and QA folks.

#### Please tell us about your environment:

- Allure version: 2.1.0
- Test framework: pytest@3.0
- Allure adaptor: allure-pytest@2.0.0b1

#### Other information

[//]: # (
. e.g. detailed explanation, stacktraces, related issues, suggestions
. how to fix, links for us to have more context, eg. Stackoverflow, Gitter etc
)

まず、allure-pytest が feature メタデータをどのように記録し、生成された Allure レポートがそれをどのように表示するかを追跡します。想定されるソースパスの形式を確認し、複数のディレクトリにあるテストから生成されたレポートに各 feature ファイルへのパスが表示されることを検証します。

索引モデルが issue の本文から書いたものです。