openssl: update page (#19629)

* update openssl page with examples

* resolve 1 of 1 review comment

* resolve 4 of 4 review comments

* resolve 3 of 3 review comments

* update the more information URL

pages/common/openssl.md

@@ -4,14 +4,34 @@
 > Some subcommands such as `req` have their own usage documentation.
 > More information: <https://docs.openssl.org/master/man1/openssl/>.
 
+- Generate a private key and encrypt the output file using AES256:
+
+`openssl genpkey -algorithm {{rsa|ec}} -out {{private.key}} -aes256`
+
+- Generate the corresponding public key from private key `private.key` using `rsa`:
+
+`openssl rsa -in {{private.key}} -pubout -out {{public.key}}`
+
+- Generate a self-signed certificate valid for a specified number of days (`365`):
+
+`openssl req -new -x509 -key {{private.key}} -out {{certificate.crt}} -days {{365}}`
+
+- Convert certificate to `pem` or `der` format:
+
+`openssl x509 -in {{certificate.crt}} -out {{certificate.pem|certificate.der}} -outform {{pem|der}}`
+
+- Check certificate details:
+
+`openssl x509 -in {{certificate.crt}} -text -noout`
+
+- Generate a certificate signing request (CSR):
+
+`openssl req -new -key {{private.key}} -out {{request.csr}}`
+
 - Display help:
 
 `openssl help`
 
-- Display help for a specific subcommand:
-
-`openssl help {{x509}}`
-
 - Display version:
 
 `openssl version`