add snapshot.lisp, implement take-snapshot and stub-out restore.

I will add to this as I add more snapshot features into the main website
code (I.E. HTML templates and routes in web.lisp). At the moment, this package
is a little island right now and doesn't integrate into the rest of the website
at all.

src/snapshot.lisp

@@ -0,0 +1,33 @@
+(in-package #:cl-user)
+(defpackage #:snapshot
+  (:use #:cl
+        #:utils
+        #:storage
+        #:nera)
+  (:export
+   #:take-snapshot
+   #:restore-from-snapshot))
+(in-package #:snapshot)
+
+(defun take-snapshot ()
+  "Takes a Snapshot of the website's data and stores it in /snapshots.
+I've not included make a SQL dump of the Meilisearch database here because the
+user can repopulate that database after they have restored this website. The
+'repopulate' feature is built into the website already."
+  (let ((snapshot-directory
+          (format nil "~a_~a/"
+                  (utils:slugify
+                   (site-settings::site-name-of (nera:get-site-settings)))
+                  (utils:create-timestamp-text))))
+    (storage:ensure-raw-directory-exists
+     (format nil "snapshots/~a" snapshot-directory))
+    (storage:copy-storage-directory
+     (format nil "snapshots/~a/storage/" snapshot-directory))
+    (storage:copy-raw-directory
+     "db/" (format nil "snapshots/~a/db/" snapshot-directory))))
+
+(defun restore-from-snapshot (snapshot-name)
+  "Deletes the data in /storage and the DB and replaces it with `SNAPSHOT-NAME'."
+  (format t "RESTORE-FROM-SNAPSHOT NOT IMPLEMENTED."))
+
+