My apologies; one can see that I mostly work with other formatting
syntax than MarkDown :(

There have been some question about the supported bands and availability
of SIM cards in the matrix chat, so let's add at least that kind of
basic information.

I'm not a POC member, but just adding general knowledge known from prior
events, which is better than an empty section.

* define who "we" is in the context of the section
* hyperlinks to osmcoom wiki pages for relevant technology
* link to etherpad where interested parties can record their location
* some technical clarifications

- Updated CERT description on behalf of blubbel
- Unified Mastodon URL representation
- Removed Ortho Imagery from CERT location URL