Add algorithms using RSA with SHA2

The recommendation for clients is very outdated not mentioning any RSA-SHA2 algorithms that are standardized for 4 years and the old RSA-SHA1 disabled in OpenSSH upstream causing interoperability problems for people following these guides

https://datatracker.ietf.org/doc/html/rfc8332
https://www.openssh.com/txt/release-8.8

Resolves: mozilla#119

docs/guidelines/openssh.md

@@ -225,7 +225,7 @@ File: `~/.ssh/config`
 # Ensure KnownHosts are unreadable if leaked - it is otherwise easier to know which hosts your keys have access to.
 HashKnownHosts yes
 # Host keys the client accepts - order here is honored by OpenSSH
-HostKeyAlgorithms [email protected],ssh-[email protected],ssh-ed25519,ssh-rsa,[email protected],[email protected],[email protected],ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
+HostKeyAlgorithms [email protected],[email protected],rsa-sha2-256-[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,[email protected],[email protected],[email protected],ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
 
 KexAlgorithms [email protected],ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
 MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,[email protected]
@@ -242,7 +242,7 @@ File: `~/.ssh/config`
 # Ensure KnownHosts are unreadable if leaked - it is otherwise easier to know which hosts your keys have access to.
 HashKnownHosts yes
 # Host keys the client accepts - order here is honored by OpenSSH
-HostKeyAlgorithms [email protected],[email protected],ssh-ed25519,ssh-rsa,[email protected],[email protected],[email protected],ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
+HostKeyAlgorithms [email protected],[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa,[email protected],[email protected],[email protected],ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
 ```
 
 ## Key generation