Requires https://phabricator.wikimedia.org/T344580
In a public (i.e. non-backend) endpoint `/wikis/{domain?}`, expose data about all wikis (or single one) so it can be consumed by the Discovery feature frontend.
The data returned per wiki should be scrubbed from non-relevant information:
```
{
"sitename": <value>
"domain": <value>
"isFeatured": <value>
"description": <value>
"logo_url": <value>
"wiki_site_stats": {
....
}
}
```
The endpoint should allow clients to query for wikis where `wikiSiteinfo.pages` is greater than 0. The public endpoint needs to be rate limited to prevent abuse. It is read only. It paginates responses.
ACs:
- [ ] a list of wikis can be retrieved by calling `GET /wikis`
- [ ] a single wiki can be retreived by calling `GET /wikis/<domain>`
- [ ] Pagination is implememted by passing `limit` and `offset` query parameters. A sensible default is used. Responses contain the total number of items.
- [ ] Rate limiting is in place