Some references could be treated as aliases

There should be improvers which would take references, verify them as valid unique aliases and add them.
Below documents refers to same RHSA but it is not sure that they are aliases to this particular advisory
Eg:
```py
"advisory": {
"identifiers": [
{
"type": "GHSA",
"value": "GHSA-6mq2-37j5-w6r6"
},
{
"type": "CVE",
"value": "CVE-2009-4492"
}
],
"summary": "Moderate severity vulnerability that affects webrick",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2009-4492"
},
{
"url": "https://github.com/advisories/GHSA-6mq2-37j5-w6r6"
},
{
"url": "http://secunia.com/advisories/37949"
},
{
"url": "http://securitytracker.com/id?1023429"
},
{
"url": "http://www.redhat.com/support/errata/RHSA-2011-0908.html"
},
{
"url": "http://www.redhat.com/support/errata/RHSA-2011-0909.html"
},
{
"url":
"http://www.ruby-lang.org/en/news/2010/01/10/webrick-escape-sequence-injection"
},
{
"url": "http://www.securityfocus.com/archive/1/508830/100/0/threaded"
},
{
"url": "http://www.securityfocus.com/bid/37710"
},
{
"url": "http://www.ush.it/team/ush/hack_httpd_escape/adv.txt"
},
{
"url": "http://www.vupen.com/english/advisories/2010/0089"
}
],
"severity": "MODERATE",
"publishedAt": "2017-10-24T18:33:38Z"
},
"package": {
"name": "webrick"
},
"vulnerableVersionRange": "<= 1.3.1"
}

```

_via: https://github.com/nexB/vulnerablecode/wiki/WeeklyMeetings#meeting-on-tuesday-2022-03-15-at-0900-utc_