Finish rewrite

[codeliner]

TODO

from #13

• Update README and Docs
• Get rid of templating component, see Rewrite to use symfony flex and prooph v7 #13 (review)
• Test different installation ways
• Release new bundle versions and require them in the demo
• Reactivate reminder email service
• Test process managers (not working atm)
• Enable snapshots and snapshot projection
• Merge prooph-do and prooph-do-symfony