EXPERIMENTAL Dev Release - Angular 20 upgrade

Update:

• [WIP] upgrade from Angular 14/15 to 20 (Thanks to @tristanpoland and @norman-abramovitz and @wayneeseguin )

Build with:

• Go: 1.25.4
• Node: v24.11.1

Notes

• The Jetstream binary replaced with v4.9.4 version
• The build process needs a manual step of running make dev-frontend to have Angular create some required files
• The Angular v20 build puts frontend files in ui/browser/ so we manually move them back to ui/ while we update the build scripts. If you use the stratos-frontend-prebuild.zip you may have to manually move them again