Implement http(s) backend

[sundowndev]

Q	A
🐛 Bug fix?	no
🚀 New feature?	yes
⚠ Deprecations?	no
❌ BC Break	no
🔗 Related issues	#176
❓ Documentation	yes snyk/driftctl-docs#17

Description

Implement a way to fetch the Terraform state from a HTTP(s) URL. User may need to fetch the Terraform state file from an external HTTP endpoint such as public Git repository or CDN. User can pass custom headers to the request to handle any auth system. This can be useful when a user wants to try out a single manifest without granting access to a whole S3 bucket. This feature should be followed by the introduction of Git backend which should allow user to fetch multiple manifests from a Git repository with proper support of authentication etc.

Examples

• Fetch a manifest from a Git repo and add a custom header to the request

$ AWS_PROFILE=my-profile driftctl scan --from tfstate+https://github.com/cloudskiff/driftctl/raw/main/pkg/iac/terraform/state/test/ec2_ami/terraform.tfstate -H 'X-Custom-Header=value'

[lotoussa]

LGTM

[codecov]

Codecov Report

Merging #335 (94032a0) into main (7928a49) will increase coverage by 0.03%.
The diff coverage is 77.41%.

@@            Coverage Diff             @@
##             main     #335      +/-   ##
==========================================
+ Coverage   69.19%   69.23%   +0.03%     
==========================================
  Files         280      281       +1     
  Lines        5966     5993      +27     
==========================================
+ Hits         4128     4149      +21     
- Misses       1481     1486       +5     
- Partials      357      358       +1     

Impacted Files	Coverage Δ
pkg/iac/terraform/state/backend/backend.go	44.44% <0.00%> (-12.70%)	⬇️
pkg/iac/terraform/state/backend/http_reader.go	86.66% <86.66%> (ø)
pkg/cmd/scan.go	82.27% <88.88%> (+0.66%)	⬆️
pkg/iac/supplier/supplier.go	85.18% <100.00%> (ø)
pkg/iac/terraform/state/terraform_state_reader.go	69.62% <100.00%> (ø)

[wbeuil]

Nice work ! I tested it with gitlab tutorial for state backend and I used my _gitlab_session cookie as Header. Just a small typo for me. Can you add something on your PR in the other repo driftctl-docs.