Remove the word LE from some installer questions

Change:

Symlink ISPConfig LE SSL certs to postfix? (y,n) [y]:

Symlink ISPConfig LE SSL certs to pureftpd? Creating dhparam file takes some times. (y,n) [y]:

to

Symlink ISPConfig SSL certs to postfix? (y,n) [y]:

Symlink ISPConfig SSL certs to pureftpd? Creating dhparam file takes some times. (y,n) [y]:

As the symlinks apply also to self-signed or officially signed SSL certs from other sources.