feat: new host - idols-akane, hardens VFAT /boot mounts (#245)

* feat: new host - idols-akane

* fix: missing efi files

* fix: efi partition - permission issue

hosts/idols-akane/README.md

@@ -0,0 +1,21 @@
+# Idols - Akane
+
+VM running on macOS's UTM App.
+
+Steps to install:
+
+```bash
+# 1. format & mount the filesystem
+nix-shell -p disko
+sudo disko --mode destroy,format,mount hosts/idols-akane/disko-fs.nix
+
+# 2. install nixos
+nixos-install --root /mnt --flake .#akane --no-root-password --show-trace --verbose --option substituters "https://mirrors.ustc.edu.cn/nix-channels/store  https://cache.nixos.org/" # install-2
+
+# enter into the installed system, check password & users
+# `su ryan` => `sudo -i` => enter ryan's password => successfully login
+# if login failed, check the password you set in install-1, and try again
+nixos-enter
+
+reboot
+```