builder: support features in inspect command

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

__tests__/buildx/builder.test.ts

@@ -415,6 +415,12 @@ describe('parseInspect', () => {
            "name": "builder0",
            "platforms": "linux/amd64,linux/amd64/v2,linux/amd64/v3,linux/arm64,linux/riscv64,linux/ppc64le,linux/s390x,linux/386,linux/mips64le,linux/mips64,linux/arm/v7,linux/arm/v6",
            "status": "running",
+           "features": {
+             "Cache export": true,
+             "Docker exporter": true,
+             "Multi-platform build": true,
+             "OCI exporter": true,
+           },
            "labels": {
              "org.mobyproject.buildkit.worker.executor": "oci",
              "org.mobyproject.buildkit.worker.hostname": "docker-desktop",

__tests__/fixtures/inspect11.txt

@@ -10,6 +10,11 @@ Status:                running
 BuildKit daemon flags: --debug --allow-insecure-entitlement security.insecure --allow-insecure-entitlement network.host --allow-insecure-entitlement=network.host
 BuildKit version:      37657a1
 Platforms:             linux/amd64, linux/amd64/v2, linux/amd64/v3, linux/arm64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/mips64le, linux/mips64, linux/arm/v7, linux/arm/v6
+Features:
+ Cache export:         true
+ Docker exporter:      true
+ Multi-platform build: true
+ OCI exporter:         true
 Labels:
  org.mobyproject.buildkit.worker.executor:         oci
  org.mobyproject.buildkit.worker.hostname:         docker-desktop