.sync/azure_pipelines/MuDevOpsWrapper.yml: Add extra_cargo_steps parameter

The `extra_cargo_steps` parameter allows a repo extending
MuDevOpsWrapper.yml to specify a step list that should be executed
before running the standard set of cargo commands in the repo
(to build and test).

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>

Author: makubacki

.sync/azure_pipelines/MuDevOpsWrapper.yml

@@ -73,6 +73,11 @@ parameters:
   displayName: Whether Rust code is being built
   type: boolean
   default: false
+- name: extra_cargo_steps
+  displayName: Extra Steps to Run Before Standard Cargo Steps
+  type: stepList
+  default:
+    - script: echo No extra cargo steps provided
 
 jobs:
 - template: Jobs/PrGate.yml@mu_devops
@@ -110,6 +115,7 @@ jobs:
     - checkout: self
       fetchDepth: 1
       clean: true
+    - ${{ parameters.extra_cargo_steps }}
     - template: Steps/RustCargoSteps.yml@mu_devops
 
 - ${{ parameters.extra_jobs }}