Use DO Spaces as a backend provider

[LouisIV]

Fixes #4

[LouisIV]

I also fixed a port assignment in the setup-tunnels script

[fmeringdal]

Great work @LouisIV !

I am wondering if creating a DO Space and secret should be a prerequisite before deploying this cluster.
The README could be updated to:

Deployment Prerequisites
- Docker
- DigitalOcean token
- DigitalOcean space and space token (link to some article that explains how to do this)
- 30 minutes

Then the docker deployment image can be started like this:

docker run \
	-e DO_TOKEN="TODO"  \
	-e DO_REGION="TODO"  \
	-e DO_SPACE_NAME="TODO"  \
	-e DO_SPACE_TOKEN="TODO"  \
	-p 4646:4646 -p 8081:8081 -p 8200:8200 -p 8500:8500 \
	-v $(pwd):/hashiplatform-deploy  \
	-it hashiplatform-deploy

Also remember that there are two terraform projects here that needs one backend each.

• The infrastructure code
• The configuration of Vault

[LouisIV]

Good point but I would like to keep the backend.hcl files. It's the recommended way of handling this exact situation. It's also nice because they make it easy to have different environments. backend.dev.hcl or stage etc.