Improve isolation, execution limits and execution metrics by using Isolate (#683)

* Initial: use Isolate for isolation

* Continue: use Isolate for isolation

* Bug fixes

* timeout is wall-time for backward compatibility

* Documentation, signal names, reported time in ms

* Report memory usage in bytes

* Add privileged flags where needed

* Remove tmpfs

* Remove tmpfs

* Fix package installation

* Fix path, fix Zig: CRLF -> LF

packages/zig/0.10.1/test.zig

@@ -1,6 +1,6 @@
-const std = @import("std");
-
-pub fn main() !void {
-    const stdout = std.io.getStdOut().writer();
-    try stdout.print("OK\n", .{});
-}
+const std = @import("std");
+
+pub fn main() !void {
+    const stdout = std.io.getStdOut().writer();
+    try stdout.print("OK\n", .{});
+}