fix: enable env vars in setup steps (and deprecate admin subcommand) (#3871)

* fix: enable env vars in setup steps (and deprecate admin subcommand)

* fix tests and error text

cmd/key/masterkey_test.go

@@ -0,0 +1,72 @@
+package key
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_checkSingleFlag(t *testing.T) {
+	type args struct {
+		masterKeyFile    string
+		masterKeyFromArg string
+		masterKeyFromEnv bool
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr assert.ErrorAssertionFunc
+	}{
+		{
+			"no values, error",
+			args{
+				masterKeyFile:    "",
+				masterKeyFromArg: "",
+				masterKeyFromEnv: false,
+			},
+			assert.Error,
+		},
+		{
+			"multiple values, error",
+			args{
+				masterKeyFile:    "file",
+				masterKeyFromArg: "masterkey",
+				masterKeyFromEnv: true,
+			},
+			assert.Error,
+		},
+		{
+			"only file, ok",
+			args{
+				masterKeyFile:    "file",
+				masterKeyFromArg: "",
+				masterKeyFromEnv: false,
+			},
+			assert.NoError,
+		},
+		{
+			"only argument, ok",
+			args{
+				masterKeyFile:    "",
+				masterKeyFromArg: "masterkey",
+				masterKeyFromEnv: false,
+			},
+			assert.NoError,
+		},
+		{
+			"only env, ok",
+			args{
+				masterKeyFile:    "",
+				masterKeyFromArg: "",
+				masterKeyFromEnv: true,
+			},
+			assert.NoError,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tt.wantErr(t, checkSingleFlag(tt.args.masterKeyFile, tt.args.masterKeyFromArg, tt.args.masterKeyFromEnv), fmt.Sprintf("checkSingleFlag(%v, %v)", tt.args.masterKeyFile, tt.args.masterKeyFromArg))
+		})
+	}
+}