chore: add ‹last_update› to docs-like posts

Allow showing ‹last updated› on the pages and also rename the files
where necessary, so they are shown in the order they were created.

Signed-off-by: Matej Focko <mfocko@redhat.com>

ib002/02-algorithms-correctness/2021-03-18-postcondition-ambiguity.md

@@ -1,4 +1,5 @@
 ---
+id: postcondition-ambiguity
 title: Vague postconditions and proving correctness of algorithms
 description: |
   Debugging and testing with precise postconditions.
@@ -7,6 +8,8 @@ tags:
 - testing
 - postconditions
 - sorting
+last_update:
+  date: 2021-03-18
 ---
 
 ## Introduction

ib002/03-time-complexity/2021-03-31-extend.mdx

@@ -1,4 +1,5 @@
 ---
+id: extend
 title: Time complexity of ‹extend›
 description: |
   How to make inefficient algorithm unknowingly.
@@ -8,6 +9,8 @@ tags:
 - dynamic array
 - time complexity
 - recursion
+last_update:
+  date: 2021-03-31
 ---
 
 import ThemedSVG from "@site/src/components/ThemedSVG";

ib002/04-recursion/2022-11-29-karel-1.md

@@ -1,4 +1,5 @@
 ---
+id: karel-1
 title: Recursion and backtracking with Robot Karel
 description: |
   A problem with too many restrictions.
@@ -7,6 +8,8 @@ tags:
 - karel
 - recursion
 - backtracking
+last_update:
+  date: 2022-11-29
 ---
 
 - [Sources](pathname:///files/ib002/karel-1)

ib002/08-rb-trees/2022-04-05-applications.md

@@ -1,4 +1,5 @@
 ---
+id: applications
 title: Použití červeno-černých stromů
 description: |
   Ukázka použití červeno-černých stromů v standardních knižnicích známých jazyků.
@@ -6,6 +7,8 @@ tags:
 - balanced trees
 - red-black trees
 - applications
+last_update:
+  date: 2022-04-05
 ---
 
 ## Použití

ib002/08-rb-trees/2023-06-10-rules.mdx

@@ -1,10 +1,13 @@
 ---
+id: rules
 title: On the rules of the red-black tree
 description: |
   Shower thoughts on the rules of the red-black tree.
 tags:
 - red-black trees
 - balanced trees
+last_update:
+  date: 2023-06-10
 ---
 
 import ThemedSVG from "@site/src/components/ThemedSVG";

ib002/10-graphs/2021-05-18-iterative-and-iterators.md

@@ -1,4 +1,5 @@
 ---
+id: iterative-and-iterators
 title: Iterative algorithms via iterators
 description: |
   Iterative DFS using iterators.
@@ -7,6 +8,8 @@ tags:
 - graphs
 - iterators
 - iterative
+last_update:
+  date: 2021-05-18
 ---
 
 ## Introduction

ib002/10-graphs/2022-04-30-bfs-tree.mdx

@@ -1,10 +1,13 @@
 ---
+id: bfs-tree
 title: Distance boundaries from BFS tree on undirected graphs
 description: |
   Short explanation of distance boundaries deduced from a BFS tree.
 tags:
 - graphs
 - bfs
+last_update:
+  date: 2022-04-30
 ---
 
 import ThemedSVG from "@site/src/components/ThemedSVG";

pb071/bonuses/03.md

@@ -3,6 +3,8 @@ id: seminar-03
 title: 3rd seminar
 description: |
   Select sort implementation on arrays.
+last_update:
+  date: 2023-03-07
 ---
 
 :::caution

pb071/bonuses/04.md

@@ -3,6 +3,8 @@ id: seminar-04
 title: 4th seminar
 description: |
   Robot in a maze.
+last_update:
+  date: 2023-03-13
 ---
 
 :::caution

pb071/pexam/b-garbage_collect.md

@@ -3,6 +3,8 @@ slug: garbage_collect
 title: Practice exam B
 description: |
   Garbage everywhere…
+last_update:
+  date: 2023-05-08
 ---
 
 # Garbage Collection

pb071/pexam/c-cams.md

@@ -3,6 +3,8 @@ slug: cams
 title: Practice exam C
 description: |
   Stalking cars…
+last_update:
+  date: 2023-05-07
 ---
 
 # Watching Cams

pb161/environment.md

@@ -2,6 +2,8 @@
 title: Environment
 description: |
   Suggestions for setting up a local environment for C++ course.
+last_update:
+  date: 2023-02-18
 ---
 
 ## Required tools per OS