[PENDING] Add new table `ssl_ciphers` to ProxySQL Admin

[JavierJF]

This PR adds a new table ssl_ciphers to ProxySQL Admin. This table allows to check the currently supported ciphers by ProxySQL. The table is populated during startup and it's never save to disk, in a similar fashion to mysql_collations table.

It's defined with two rows cipher_name and cipher_description. A simple output for completion:

mysql> SELECT * FROM ssl_ciphers LIMIT 2;
+------------------------------+-------------------------------------------------------------------------------------------------+
| cipher_name                  | cipher_description                                                                              |
+------------------------------+-------------------------------------------------------------------------------------------------+
| TLS_AES_256_GCM_SHA384       | TLS_AES_256_GCM_SHA384         TLSv1.3 Kx=any      Au=any   Enc=AESGCM(256)            Mac=AEAD |
| TLS_CHACHA20_POLY1305_SHA256 | TLS_CHACHA20_POLY1305_SHA256   TLSv1.3 Kx=any      Au=any   Enc=CHACHA20/POLY1305(256) Mac=AEAD |
+------------------------------+-------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

[renecannao]

Table definitions like ADMIN_SQLITE_TABLE_SSL_CIPHERS is being moved away from ProxySQL_Admin.cpp . Putting this PR on hold until that migration is completed.

[mirostauder]

Can one of the admins verify this patch?