refactor: move cmd/ftl to frontend/cli #6730

Job	Run time
Rebuild All	0s
Console e2e	0s
Console	1m 30s
Lint Architecture	10s
Build Box Docker Image	0s
Build Controller Docker Image	0s
Build Runner Docker Image	0s
Build Docs	11s
Ensure Frozen Migrations	11s
Shard Integration Tests	0s
Lint	1m 41s
VSCode Extension	1m 18s
Intellij Plugin	0s
Proto Breaking Change Check	12s
SQL	51s
Test Go	2m 59s
Test README	1m 47s
Test Scripts	8s
Integration Test	0s
Integration Success	1s
	10m 59s

Provide feedback