Move terraform-state to b2

The terraform-state can be stored in backblaze b2 with some
configurations. This changes does exactly this. Note, that this requires
the special env-variables `AWS_SECRET_ACCESS_KEY` and
`AWS_ACCESS_KEY_ID` which are normally part of the AWS-setup. To be able
to use AWS and this setup in parallel I use dotenv to maintain the
variables in the special file `.envrc`.

Reference: https://andrzejgor.ski/posts/backblaze_b2_tf_state
Reference: https://www.reddit.com/r/selfhosted/comments/1iv1qir
Reference: https://direnv.net/

.gitignore

@@ -3,6 +3,7 @@ inventory.*
 README.*
 !README.adoc
 password.txt
+.envrc
 
 # Created by https://www.toptal.com/developers/gitignore/api/vim,ansible,jetbrains,terraform
 # Edit at https://www.toptal.com/developers/gitignore?templates=vim,ansible,jetbrains,terraform