allure-robotframework not supporting link issue pattern

#### 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?
When creating allure results with allure-robotframework it doesn't support parameterized way for creating prefix for issue links. For example if robot test contains TAG "issue:myIssueId", allure results (and generated allure report) will contain URL into host where allure report is served (like http://10.251.83.101:65165/myIssueId).

Current workaround is to place URL into test TAG, e.g. issue:https://myJira.com/browse/myIssueId, This shows whole URL in the linkname on allure report.

#### What is the expected behavior?
Possibility to have parameterized base URL to issue tracking system that is copied in the front of issueId instead host where report is served. For example command line switch or property file that includes key-value pair like "allure.link.issue.pattern=https;//myJira.com/browse/". Then allure robotframework listener should add this value in front of issue link URL.

#### What is the motivation / use case for changing the behavior?
Generated allure report link section is more readable, when link name is shorter and URL is not shown on the report.

#### Please tell us about your environment:

- Allure version: 2.1.0
- Test framework: allure-python 2.9.43
- Allure adaptor: allure-robotframework 2.9.43

Inizia con il listener allure-robotframework che elabora i valori di Robot TAG e verifica come vengono creati i collegamenti alle issue. Controlla i punti di ingresso della configurazione esistenti tramite la riga di comando o il file delle proprietà; il lavoro è completato quando un URL di base configurabile per i collegamenti alle issue antepone un ID di issue, mentre il report mostra il nome del collegamento più breve.

Scritto dal modello di indicizzazione a partire dal testo della issue.