Add DefaultAzureCredential auth flow diagram (#4654)

* Add DefaultAzureCredential auth flow diagram

* Update cspell.json

---------

Co-authored-by: Anton Kolesnyk <41349689+antkmsft@users.noreply.github.com>

.vscode/cspell.json

@@ -97,6 +97,7 @@
     "LPSTR",
     "LPWSTR",
     "MHSM",
+    "mmdc",
     "moxygen",
     "MSAL",
     "MSRC",
@@ -154,6 +155,7 @@
     "usgoviowa",
     "usgovvirginia",
     "vcpkg",
+    "Verdana",
     "Viet",
     "Viktor",
     "vusg",

sdk/identity/azure-identity/img/mermaidjs/DefaultAzureCredentialAuthFlow.md

@@ -0,0 +1,19 @@
+```mermaid
+%% STEPS TO GENERATE IMAGE
+%% =======================
+%% 1. Install mermaid CLI (see https://github.com/mermaid-js/mermaid-cli/blob/master/README.md)
+%%    v10.0.2 is known good for our process. npm install -g @mermaid-js/mermaid-cli@10.0.2
+%% 2. Run command: mmdc -i DefaultAzureCredentialAuthFlow.md -o DefaultAzureCredentialAuthFlow.svg
+
+flowchart LR;
+    A(Environment):::deployed ==> B(Azure CLI):::developer ==> C(Managed Identity):::deployed;
+
+    subgraph CREDENTIAL TYPES;
+        direction LR;
+        Deployed(Deployed service):::deployed ~~~ Developer(Developer):::developer;
+    end;
+
+    %% Define styles for credential type boxes
+    classDef deployed fill:#95C37E, stroke:#71AD4C;
+    classDef developer fill:#F5AF6F, stroke:#EB7C39;
+```