feat: examples for terraform doc

[leiicamundi]

This PR adds examples files of our terraform guide for Camunda 8 deployment. Automated tests are not part of this PR.

This PR also introduce a breaking change related to the modules, changing the behavior of the roles from a single role input variable to a list, therefore a v3 will be released after the merge.

[Langleu]

have overflown it as part of the documentation review. Looks overall good.

I'll do a test run of one path tomorrow and as part of that look at some files in more detail.

[leiicamundi]

Thanks for the review @Langleu
If you test the examples, don't forget to replace ref=3.0.0 by this branch.

I have also added a new folder for 8.7 and this PR was tested only for 8.6

[leiicamundi]

FYI, I've added a doc regarding the deletion of the EKS Cluster and a new variable to configure the EBS Storage.
I've also updated the config part to let the user providing his s3 bucket.

[Langleu]

tested eksctl + standard last week and terraform + irsa based on the Documentation PR that's related to this.

[leiicamundi]

Thank you! Merging this an releasing the 3.0.0 version 🐰