Add integration with "external" boards for gathering answers

[yarikoptic]

Many projects have public boards, dedicated like https://discuss.afni.nimh.nih.gov/ or common like http://neurostars.org/ with dedicated tags (both are discourse) , there are also matrix channels etc. It would be awesome if we could also use them as a resource to find answers since many could be answered there. In addition to discourse actively used are

• slack (there is slackdump to dump)
• github discussions (not yet sure what has to dump)
• matrix (we have home brewed archival script https://github.com/con/versations)
• mattermost

so if dump is available -- would be great to search through it, otherwise -- through API / MCP