Devcontainer additions (#2029)

Add extensions for:

* Bicep 
* .NET test runner
* Azure Functions

Include in setup script:

* `cargo-audit` & `cargo-license` (pre-reqs for the CI script)

.devcontainer/devcontainer.json

@@ -25,7 +25,10 @@
 		"tamasfe.even-better-toml",
 		"serayuzgur.crates",
 		"ms-dotnettools.csharp",
-		"ms-python.python"
+		"ms-python.python",
+		"ms-azuretools.vscode-bicep",
+		"formulahendry.dotnet-test-explorer",
+		"ms-azuretools.vscode-azurefunctions"
 	],
 	// Use 'forwardPorts' to make a list of ports inside the container available locally.
 	// "forwardPorts": [],

.devcontainer/post-create-script.sh

@@ -19,6 +19,7 @@ sudo cp ./azcopy_linux_amd64_*/azcopy /usr/bin/
 
 # Restore rust dependencies
 echo "Restoring rust dependencies"
+cargo install cargo-audit cargo-license # requirements if you want to run ci/agent.sh
 cd /workspaces/onefuzz/src/agent
 cargo fetch