enhancement: scan terraform registry modules as remote type

[patilpankaj212]

1. Added support for scanning terraform registry as remote type
2. Refactored code and modified tests

User can now run below to scan terraform remote modules in terraform registry. eg:

terrascan scan -r terraform-registry -u terraform-aws-modules/eks/aws:13.2.1

[codecov]

Codecov Report

Merging #513 (50d64c3) into master (9088544) will increase coverage by 0.77%.
The diff coverage is 96.66%.

@@            Coverage Diff             @@
##           master     #513      +/-   ##
==========================================
+ Coverage   75.57%   76.35%   +0.77%     
==========================================
  Files          94       94              
  Lines        2227     2258      +31     
==========================================
+ Hits         1683     1724      +41     
+ Misses        401      396       -5     
+ Partials      143      138       -5     

Impacted Files	Coverage Δ
pkg/cli/register.go	5.55% <0.00%> (-0.70%)	⬇️
pkg/iac-providers/terraform/commons/load-dir.go	85.13% <96.00%> (+2.27%)	⬆️
pkg/cli/scan.go	77.77% <100.00%> (ø)
pkg/downloader/getter.go	86.36% <100.00%> (+3.67%)	⬆️
pkg/downloader/interface.go	100.00% <100.00%> (ø)
pkg/downloader/module-download.go	91.56% <100.00%> (ø)
pkg/downloader/remote-modules.go	100.00% <100.00%> (ø)

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

No Coverage information
0.0% Duplication

[jlk]

LGTM!