Update to the splash screen credits

[OnlineCop]

• Moves the functions for setting up and displaying credits into its own KCredits class.
• Adds a parameter to display_credits() to make the ease in/out speed adjustable.
• Updated the copyright year from 2021 to 2022.
• Added this repo's URL to the list.

I did not rearrange the existing credits, although I was sorely tempted to do so.

Also @teamterradactyl: Do you want your real name in there, or do you want to leave your pseudonym as-is?

[pedro-w]

Do you want to re-arrange the credits? I don't particularly want to go 'first' (after JB of course)

[OnlineCop]

I have no idea how the original ordering came about. Maybe by order of contributions to the original source code or help provided in the Allegro forums? Maybe some kind of early alphabetical order that fell into disuse?

I could do alphabetical by first or last name (*cough* @TeamTerradactyl *cough*), or some other sort method.

[pedro-w]

Possibly could randomize them with something like:

commit aed8fecaeb736be070da0c5a19b76c990eebebcf
Author: Peter Hull <peterhull90@gmail.com>
Date:   Mon Jul 25 21:49:10 2022 +0100

    Randomize the credits

diff --git a/src/credits.cpp b/src/credits.cpp
index 64d2b98..644a55b 100644
--- a/src/credits.cpp
+++ b/src/credits.cpp
@@ -34,2 +34,3 @@
 #include "gfx.h"
+#include "random.h"

@@ -40,2 +41,4 @@

+using std::swap;
+
 std::vector<std::string> credits { "Josh Bolduc",
@@ -76,2 +79,8 @@ void KCredits::allocate_credits()
 {
+    // Randomize the credits from item 5 to the end
+    for (int rounds = 0; rounds < credits.size(); ++rounds)
+    {
+        int index = kqrandom->random_range_exclusive(6, credits.size());
+        swap(credits[5], credits[index]);
+    }
     if (wk == nullptr)
diff --git a/src/kq.cpp b/src/kq.cpp
index d0df459..8ee2786 100644
--- a/src/kq.cpp
+++ b/src/kq.cpp
@@ -335,3 +335,3 @@ int main(int argc, char* argv[])
     game_on = 1;
-    kqrandom = new KQRandom();
+
     /* While KQ is running (playing or at startup menu) */
@@ -672,2 +672,3 @@ void KGame::allocate_stuff()
 #endif
+    kqrandom = new KQRandom();
     Credits.allocate_credits();

It turns out I added the first version of credits.c (in 2003) and therefore it was me putting my own name first. What a cheek!

[OnlineCop]

I like the name randomization idea. Added (with a minor tweak to the range).