feat: add "Maintained by SAP" badge to CDC Starter Kit project

Added visual badge to show CDC Starter Kit is now maintained by SAP:

1. Go struct changes:
   - Added MaintainedBy field to Project struct (cv.go:108)

2. Data updates:
   - Added "maintainedBy": "SAP" to CDC Starter Kit in cv-en.json
   - Added "maintainedBy": "SAP" to CDC Starter Kit in cv-es.json

3. Template changes:
   - Added maintained-badge display in project header (cv-content.html:226-228)
   - Shows "MAINTAINED BY SAP" (EN) or "MANTENIDO POR SAP" (ES)

4. CSS styling:
   - Added .maintained-badge style with blue background (#3498db)
   - Matches current-badge and expired-badge styling

Badge appears next to project title to highlight SAP's ongoing maintenance.

templates/cv-content.html

@@ -223,6 +223,9 @@
                                 {{if .Current}}
                                     <span class="current-badge">{{if eq $.Lang "es"}}ACTUAL{{else}}CURRENT{{end}}</span>
                                 {{end}}
+                                {{if .MaintainedBy}}
+                                    <span class="maintained-badge">{{if eq $.Lang "es"}}MANTENIDO POR{{else}}MAINTAINED BY{{end}} {{.MaintainedBy}}</span>
+                                {{end}}
                             </h4>
                             <span class="project-period">{{.StartDate}} {{if .Current}}/ {{if eq $.Lang "es"}}presente{{else}}now{{end}}{{end}}</span>
                             <span class="project-separator">&nbsp;-&nbsp;</span>