[ENH] Plugin Cypht: Change parameters

Here are the changes implemented:

• IMAP account name change: from Account mailbox to IMAP connection name;
• Changing the IMAP account description;
• Change for username: from Account mailbox username to Account IMAP username;
• Change for password: from Account mailbox password to Account IMAP password;
• Change the description for the SMTP account;
• Changed the value of the "default" parameter for smtp_no_auth, use_global_settings, groupmail;
• Adding default options to the parameters smtp_no_auth, use_global_settings, groupmail;
• And added two new parameters: smtp_username and smtp_password ;
• Also, for the imap_password, I changed the type of field, from text to password.