chore: add discontinuation notices

bye bye eifueo :(

docs/1a/ece105.md

@@ -1,5 +1,10 @@
 # ECE 105: Classical Mechanics
 
+!!! warning
+    <p style="font-size: 1rem">**The Eifueo project is no longer maintained
+    as of 19 April 2023. Information in this repository may no longer be accurate.
+    Please see [the main blog post](https://eggworld.me/blog/2023/sunsetting-eifueo) for more details.**</p>
+
 ## Motion
 
 Please see [SL Physics 1#2.1 - Motion](/g11/sph3u7/#21-motion) for more information.

docs/1a/ece150.md

@@ -1,5 +1,10 @@
 # ECE 150: C++
 
+!!! warning
+    <p style="font-size: 1rem">**The Eifueo project is no longer maintained
+    as of 19 April 2023. Information in this repository may no longer be accurate.
+    Please see [the main blog post](https://eggworld.me/blog/2023/sunsetting-eifueo) for more details.**</p>
+
 ## Non-decimal numbers
 
 Binary numbers are prefixed with `0b`.

docs/1a/math115.md

@@ -1,5 +1,10 @@
 # MATH 115: Linear Algebra
 
+!!! warning
+    <p style="font-size: 1rem">**The Eifueo project is no longer maintained
+    as of 19 April 2023. Information in this repository may no longer be accurate.
+    Please see [the main blog post](https://eggworld.me/blog/2023/sunsetting-eifueo) for more details.**</p>
+
 ## Set theory
 
 !!! definition

docs/1a/math117.md

@@ -1,5 +1,10 @@
 # MATH 117: Calculus 1
 
+!!! warning
+    <p style="font-size: 1rem">**The Eifueo project is no longer maintained
+    as of 19 April 2023. Information in this repository may no longer be accurate.
+    Please see [the main blog post](https://eggworld.me/blog/2023/sunsetting-eifueo) for more details.**</p>
+
 ## Functions
 
 A **function** is a rule where each input has exactly one output, which can be determined by the **vertical line test**.