feat!: architecture support

[matt-FFFFFF]

Adds support for architecture definition being part of the library.

See here for an architecture definition: https://github.com/Azure/Azure-Landing-Zones-Library/blob/main/platform/alz/architecture_definitions/alz.alz_architecture_definition.json

Removes ability to add MGs via the exported API.

ToDo:

• [x] Move additional policy role assignments to hierarchy level not MG
• [x] Add methods to get data from hierarchy for use by callers
• [x] Fix example

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 35.71429% with 261 lines in your changes missing coverage. Please review.

Project coverage is 43.20%. Comparing base (106b88f) to head (099bd2e). Report is 78 commits behind head on main.

Files	Patch %	Lines
deployment/hierarchy.go	0.95%	104 Missing :warning:
alzlib.go	36.29%	73 Missing and 6 partials :warning:
archetype.go	0.00%	23 Missing :warning:
deployment/managementgroup.go	55.76%	21 Missing and 2 partials :warning:
architecture.go	61.81%	17 Missing and 4 partials :warning:
assets/policyDefinition.go	33.33%	6 Missing :warning:
assets/policyAssignment.go	50.00%	3 Missing :warning:
processor/libArchitecture.go	90.90%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #116 +/- ## =========================================== - Coverage 70.66% 43.20% -27.46% =========================================== Files 6 16 +10 Lines 900 1178 +278 =========================================== - Hits 636 509 -127 - Misses 193 570 +377 - Partials 71 99 +28 ```

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