Disallow embed-resources for Book and Website project ?

[cderv]

This options is probably not meant to be working with Website ou Book

We have two cases of problem known so far:

• failed to allocate string buffer exceeds maximum length on a book project when embedding resources #11311
• quarto render fails when enabling self-contained or embed-resources in yaml #11206

It seems right to completely disallow this options, either by erroring, or by warning and ignoring.