net_ssl: Switch to elliptic curve SSL certificates

[jeffro256]

I opened an eariler to PR to make our net_ssl RSA certificate generation code to comply with OpenSSL 3.0, but @hyc suggested that we switch to elliptic curve SSL certificates since they are smaller and faster. These PR also complies with OpenSSL 3.0.

[hyc]

I suggested we think about it. Haven't seen much other discussion yet.

[selsta]

Both patches exist now, guess we can talk about it in the next dev meeting.

[jeffro256]

@hyc Yes, sorry should've clarified "suggested". I definitely welcome discussion about why this is a bad idea or not.

[selsta]

@vtnerd probably has an opinion on this too

[selsta]

Can you force push here to rerun CI?

[jeffro256]

rebased against master

[jeffro256]

I couldn't find a reliable cross-platform solution that didn't use non-rigid cryptography