New rule: No over-separating modules in an MVC style

[jfmengels]

What problems does it solve:

The official guide explains the problem quite well.

What the rule should do:

Report when it looks like parts of the projects are structured like an MVC construct, separated into multiple files. So if you have multiples files named Xyz.<name> where at least two of the names is Model, View, Update, ..., then they should be reported.

Example of things the rule would report:

-- src/SideBar/Model.elm
module SideBar.Model exposing (Model)
               ^^^^^
-- src/SideBar/Update.elm
module SideBar.Update exposing (Msg, update)
               ^^^^^^
-- src/SideBar/View.elm
module SideBar.View exposing (view)
               ^^^^

The ^^^^ indicate where I think the error should appear.

The same issue should also be reported if the module names are not prefixed.

-- src/Model.elm
module Model exposing (Model)
       ^^^^^
-- src/Update.elm
module Update exposing (Msg, update)
       ^^^^^^
-- src/View.elm
module View exposing (view)
       ^^^^

The contents of the module and what it exposes should not matter.

Example of things the rule would not report:

No apparent over-separation from the module name

module SideBar exposing (Model, Msg, view, update)

Only a single oddly named module per "component", which likely indicates an odd naming for the module, but not an over-separation problem.

-- src/SideBar/Model.elm
module SideBar.Model exposing (Model)
-- src/Header/Update.elm
module Header.Update exposing (Msg, update)

When (not) to enable this rule:

This rule will only be useful for applications.

I am looking for:

• Someone to implement it (I can provide help and guidance)
• A good rule name. NoMVCSeparation, NoOverSeparatingModules?
• What names should be reported.

Model, View, Update, Subscriptions. Types? Maybe also Msg and/or Init? Let me know what you have seen used!
Lamdera needs a Types.elm module at the root of the project, but as long as users don't create another module with a "smelly" name, it should be fine.