Add blurb to Practice Exercise .meta/config.json files (#494)

Each Practice Exercise will have to define a blurb, which is a short description of the exercise.
The blurb will be displayed on a track's exercises page (e.g. https://exercism.lol/tracks/csharp/exercises).

For Practice Exercises that are based on an exercise defined in the problem-specification repo, the blurb must match the contents of the problem-specifications exercises, which is defined in its `metadata.yml` file. In this commit, we'll do an initial syncing of the blurb. The new [configlet](https://github.com/exercism/configlet) version will add support for doing this syncing automatically.

If the Practice Exercise was _not_ based on a problems-specifications exercise, we've used the blurb from its `.meta/metadata.yml` file as the blurb in the .meta/config.json file.

See [the spec](https://github.com/exercism/docs/blob/main/anatomy/tracks/practice-exercises.md#file-metaconfigjson) for more information.

Author: ErikSchierboom

exercises/practice/acronym/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Convert a long phrase to its acronym",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/affine-cipher/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Create an implementation of the Affine cipher, an ancient encryption algorithm from the Middle East.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/all-your-base/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Convert a number, represented as a sequence of digits in one base, to any other base.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/allergies/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/anagram/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Given a word and a list of possible anagrams, select the correct sublist.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/armstrong-numbers/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Determine if a number is an Armstrong number",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/atbash-cipher/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/beer-song/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/binary-search/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Implement a binary search algorithm.",
   "authors": [],
   "files": {
     "solution": [],

exercises/practice/bob/.meta/config.json

@@ -1,4 +1,5 @@
 {
+  "blurb": "Bob is a lackadaisical teenager. In conversation, his responses are very limited.",
   "authors": [],
   "files": {
     "solution": [],