feat(admin): add rough initial planning

admin/planning.typ

@@ -0,0 +1,18 @@
+#set text(font: "Source Sans 3")
+
+= General Planning
+
+#table(
+  columns: (auto, 1fr),
+  align: (center, left + horizon),
+  table.header[*Week*][*Objectives*],
+  [*1*], [Kickoff, setup project, start prototyping a syntax],
+  [*2*], [Syntax prototype, simple parser, discuss with Prof. Mermoud and Prof. Lettry],
+  [*3*], table.cell(rowspan: 4)[Implement a type checker],
+  [*4*],
+  [*5*],
+  [*6*],
+  [*7*], table.cell(rowspan: 3)[Code generator, refinements, report],
+  [*8*],
+  [*9*],
+)