Move documentation to MkDocs and add comprehensive guides

Reorganized documentation to be part of MkDocs site with three new
comprehensive guides covering API7 Gateway configuration.

Changes:

1. Documentation Structure:
   - Moved SECRET-MANAGEMENT.md from helm/ to web/docs/
   - Created service-discovery.md with complete guide
   - Created ingress-routing.md with routing architecture
   - Moved externalsecret examples to web/docs/examples/

2. New Documentation - Service Discovery:
   - How service discovery works (architecture diagram)
   - Benefits vs static configuration
   - Configuration examples
   - RBAC requirements
   - Advanced use cases (auto-scaling, rolling updates)
   - Load balancing algorithms
   - Monitoring and troubleshooting
   - Best practices

3. New Documentation - Ingress & Routing:
   - Complete traffic flow architecture
   - Ingress configuration explained
   - Gateway routing rules and priority
   - URI matching patterns (prefix, exact, regex)
   - TLS/SSL with cert-manager
   - Advanced routing scenarios:
     * Multiple domains
     * Path-based routing
     * Header-based routing
     * Method-based routing
   - Configuration examples (microservices, WebSocket, canary)
   - Monitoring and debugging
   - Troubleshooting common issues

4. MkDocs Navigation:
   - Updated mkdocs.yml with new pages in Configuration section
   - Added: Ingress & Routing
   - Added: Service Discovery
   - Added: Secret Management

5. Examples Directory:
   - Created web/docs/examples/ for configuration examples
   - Moved ExternalSecret examples with multiple providers:
     * AWS Secrets Manager
     * HashiCorp Vault
     * Azure Key Vault
     * GCP Secret Manager

All documentation now integrated into MkDocs site with proper
navigation, cross-references, and Material theme styling.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

helm/api7ee-demo-k8s/templates/externalsecret-api7.yaml.example

@@ -1,93 +0,0 @@
-# Example ExternalSecret for API7 Gateway credentials
-# This file is not deployed by default - it serves as an example.
-#
-# To use External Secrets Operator:
-# 1. Install External Secrets Operator in your cluster
-# 2. Configure a SecretStore (e.g., AWS Secrets Manager, Vault, etc.)
-# 3. Rename this file to remove .example extension
-# 4. Set api7.gateway.existingSecret to the secret name below
-# 5. Adjust the backend configuration to match your SecretStore
-#
-# Documentation: https://external-secrets.io/
-
-{{- if false }}  # Change to 'if .Values.api7.gateway.useExternalSecret' to enable
-apiVersion: external-secrets.io/v1beta1
-kind: ExternalSecret
-metadata:
-  name: {{ include "api7ee.fullname" . }}-api7-admin-external
-  labels:
-    {{- include "api7ee.labels" . | nindent 4 }}
-    app.kubernetes.io/component: api7
-spec:
-  # Refresh interval for fetching secrets from external provider
-  refreshInterval: 1h
-
-  # Reference to SecretStore
-  secretStoreRef:
-    name: vault-backend  # Name of your SecretStore
-    kind: SecretStore    # or ClusterSecretStore
-
-  # Target Secret configuration
-  target:
-    name: {{ include "api7ee.fullname" . }}-api7-admin
-    creationPolicy: Owner
-    template:
-      type: Opaque
-      data:
-        # Map external secret keys to Kubernetes secret keys
-        admin-url: "{{ `{{ .adminUrl }}` }}"
-        admin-key: "{{ `{{ .adminKey }}` }}"
-        gateway-group: "{{ `{{ .group }}` }}"
-
-  # Data to fetch from external provider
-  data:
-    - secretKey: adminUrl
-      remoteRef:
-        key: api7/gateway    # Path in external secret store
-        property: admin_url  # Property name
-
-    - secretKey: adminKey
-      remoteRef:
-        key: api7/gateway
-        property: admin_key
-
-    - secretKey: group
-      remoteRef:
-        key: api7/gateway
-        property: gateway_group
-
----
-# Example for AWS Secrets Manager
-# apiVersion: external-secrets.io/v1beta1
-# kind: SecretStore
-# metadata:
-#   name: aws-secretsmanager
-# spec:
-#   provider:
-#     aws:
-#       service: SecretsManager
-#       region: us-east-1
-#       auth:
-#         jwt:
-#           serviceAccountRef:
-#             name: external-secrets-sa
-
----
-# Example for HashiCorp Vault
-# apiVersion: external-secrets.io/v1beta1
-# kind: SecretStore
-# metadata:
-#   name: vault-backend
-# spec:
-#   provider:
-#     vault:
-#       server: "https://vault.example.com"
-#       path: "secret"
-#       version: "v2"
-#       auth:
-#         kubernetes:
-#           mountPath: "kubernetes"
-#           role: "api7-role"
-#           serviceAccountRef:
-#             name: {{ include "api7ee.serviceAccountName" . }}
-{{- end }}