[Opendnssec-develop] ods-kaspcheck requirements

[Rickard Bellgrim]

> They seem sensible on a quick look through; if anyone would like to comment
> on them, or update them, now would be a good time ;) .

I have added some more information on the key size checks:

***
The key strength should be checked for sanity
- warn if less than 1024 or error if more than 4096. Only do this check for RSA.
***

We should error if the key size is larger than 4096, because that is
not supported in DNSSEC. And this only apply to RSA.