Fix Edge CA cert to create P-256 / RSA-4096 key pairs.

[arsing]

Ref: Azure/iot-identity-service#403

[gordonwang0]

There's a backlogged work item to make this configurable instead of hardcoded to these algorithms. But making it consistent is a good start.

[arsing]

Ah yes, I see the work item you're talking about. It's true that configurable would be nice to have. It would also solve the problem with module certs issued through the workload API - they're currently hard-coded to RSA-2048 but I did not change them in this PR because there's no way to have them match the issuer cert's key algorithm. But if we allow the user to configure it then we can let the user make sure the algorithms match.

[arsing]

In shiproom we decided to do this after the next release branch is branched, and to implement a configuration option for this to reduce the chance of regression from switching from RSA to EC certs. So I've marked this is Draft for now.

[buentead]

I was wondering if there is an ETA for this PR to merge into main branch as I'm waiting for the fix of EST ID and Device ID certificates default to using different key types #403. Thanks.