templates: adds Reusable Content Block to website templates

[zubricks]

• adds Reusable Content Block
• updates config / Pages to use block references

[paulpopus]

This should be copied over to other template variations too. You can do that by running the script:gen-templates command, it will regenerate migrations and stuff too so pick and choose the right files to commit after running this

with-vercel-website should get the same changes

edit: to add we should start writing e2es in the test folder if you can add one to verify that you can add this block into a page collection please