Mattermost publicly searchable channels

Hi @psuzzi,

Thanks for your question, we love to see the Eclipse community using Mattermost, and also contributing back,

Publicly searching channels isn't currently available. Would highly appreciate your help adding a feature idea which can be discussed and upvoted,

Alternatively, the Web Service API could probably be used to add this outside the product. API documentation is not fully implemented, but you can examine the Javascript and Golang drivers to figure out how to access the APIs needed for this.