Add support for arm linked templates

[sigmabaryon]

• Add support for linked templates
• Better unit tests

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities
0 Security Hotspots
3 Code Smells

No Coverage information
0.0% Duplication

[codecov]

Codecov Report

Merging #903 (84dc8d8) into master (9e962b9) will decrease coverage by 0.24%.
The diff coverage is 67.78%.

@@            Coverage Diff             @@
##           master     #903      +/-   ##
==========================================
- Coverage   79.08%   78.84%   -0.25%     
==========================================
  Files         211      213       +2     
  Lines        5117     5223     +106     
==========================================
+ Hits         4047     4118      +71     
- Misses        826      854      +28     
- Partials      244      251       +7     

Impacted Files	Coverage Δ
pkg/mapper/iac-providers/arm/config/deployments.go	48.48% <48.48%> (ø)
pkg/mapper/iac-providers/arm/arm.go	85.00% <66.66%> (+0.38%)	⬆️
pkg/iac-providers/arm/v1/load-file.go	70.83% <70.21%> (-1.23%)	⬇️
...per/iac-providers/arm/functions/linked-template.go	89.47% <89.47%> (ø)