If I understand correctly, your goal is to have an installer to install the certificate and edit configuration files on apache or nginx.
Well, I don;t need such a thing. It would complicate my life.
I know what a CRT is, I know how to configure my applications for SSL but above all this, I use SSL with several applications, namely apache, nginx, exim AND dovecot.
I do not want to reconfigure any application each and every time a new certificate must be issued/renewed. Ever.
So each and every application is pre-configurated once and for all. They’re all pointing to the same PEM and KEY files in some directory. All I need to do is to symlink those 2 to the real thing.
This method has proven to be extremely fast.
So my first question is: Will it be possible for you to issue a certificate to me and let me install it as I see fit? All I need is the thing. I don’t need any installer. Ever.
My second question is and is an important one. Will the certificate issued be valid for the bare domain and the www subdomain as well?