Make elasticserach.test-with-ssl plugin more generic

[jkakavas]

#57319 is awesome, but we could enhance it so that it can be used by many subprojects and in fips tests

1. We should generate a CA that signs our certificates and then make all the key and certificate material available to the nodes in all formats:

• Setup a CA key and certificate
• Generate test-node private key and certificate signed by that CA
• Generate test-client private key and certificate signed by that CA
• Make all the above available as PEM files ( x.crt and x.key ) and in JKS / PKCS12 keystores
• Copy all of them as extra config files

2. We should cater for tests running in FIPS where we should use PEM files instead of JKS/PKCS12 keystores

*.ssl.key
*.ssl.secure_key_passphrase
*.ssl.certificate

instead of

*.ssl.keystore.path
*.ssl.keystore.secure_password

and

*.ssl.certificate_authorities

instead of

*.ssl.keystore.path

or

*.ssl.truststore.path

[elasticmachine]

Pinging @elastic/es-core-infra (:Core/Infra/Build)

[breskeby]

@jkakavas after you added #66554 a while ago, what's missing from calling this issue resolved?

[jkakavas]

I think that #66554 takes care of 2. above. I'm not sure if 1. is still needed or if we still want to do this, I will defer to @elastic/es-security 🙏