Present change logs to users in the client

[williamboman]

Since our change logs are very informative (:clap: @astorije) I think users would appreciate reading a curated list of changes should their instance be upgraded. This could be presented through a modal once a user authenticates after a server upgrade. This'll also help make new features like #400 less hidden.

This could be tracked by keeping something like this in the user configs;

{
    ...
    "changelogs": {
        "enabled": true,
        "lastRead": "2.0.0-rc.1"
    }
}

[astorije]

This is a very good idea, but I think we have a long way to go, and this is probably not going to be priority.
#388 is kind of a mandatory prerequisites.
Then I'm thinking initiatives such as #610 will make these things easier to do.