Configurable cabal strictness

At work we're trying to set up a private hackage repository which can host our libraries and any software which uses those libraries. We got hackage-server up and running OK, but when we tried to upload packages to it, we got some error messages, which I believe come from "cabal check":

```
* The 'license' field is missing or specified as AllRightsReserved.

* 'ghc-options: -Wall -Werror' makes the package very easy to break with
future GHC versions because new GHC versions often add new warnings. Use just
'ghc-options: -Wall' instead.
```

For the first, we think `AllRightsReserved` is the "correct" license for not-open-source software that we do not want to distribute outside the company.

For the second, we would like to use `-Werror` as a programmatic way to enforce that code should not have warnings. We understand that in the wider world of the Internet, `-Werror` can cause problems, but we think that within the controlled environment of our company, we can manage with it. (If a new version of GHC finds something to warn about in a library, we will immediately fix the library.)

It seems to me that Hackage/Cabal should provide some setting where as administrators of the Hackage server, we can tell it, "No, really, `-Werror` and `AllRightsReserved` are OK". However, I couldn't find any such setting.