Build an "in-game event" service [backend component issue]

Scope

A game that is static and where there's never anything happening is boring
A game master of Planet A can influence the CO2 in the Air contract. That might be weird to players watching the dashboard carefully. It'd hence be great if we the game masters had a reason for CO2 decreasing in the air
In a specific case, the game might also end with a "GAME OVER", but so far there's no infrastructure or condition that would tell the players that the game is now officially over
Additionally, it might simply be funny to display:
- random imaginary events that happened in the game e.g. "a vulcano broke out guys, you're all fucked" or "we found a new continent and guess what, there's lots of trees so the end of the world is not just yet here. Ah and also or course those trees didn't produce CO2 before nevermind"

NOTE: This issue is split in two. This particular issue handles the backend part.

Build a web server (with the technology you prefer) to allows a game master (with credentials!) to send a message to players
Most of this is optional, given time constraints but we'd like to have:
- A way to send a message to a specific address e.g. "Hey Player Rio Tinto, come to the Assembly/Support both because we have a special gift for you"
- A way to send a message to a country, e.g. "All players of USB, please dance now to earn extra points"
- A way to send a message to all players, e.g. "GAME OVER" or "YOU'VE WON!"

Further requirements:

Ideally, this way of sending messages to the burner wallet is really generic so that we the game masters can do funny things. I'm thinking: Why not have the burner wallet download some HTML code and insert it dynamically into the view.
We probably don't want to insert JS into the view dynamically. But hey, no risk no fun 😆

bounty gardener: @TimDaub / 10% bounty worker: @TimDaub / 75% bounty reviewer: name / 15%