LibUnicode+Everywhere: Merge LibLocale back into LibUnicode

LibLocale was split off from LibUnicode a couple years ago to reduce the
number of applications on SerenityOS that depend on CLDR data. Now that
we use ICU, both LibUnicode and LibLocale are actually linking in this
data. And since vcpkg gives us static libraries, both libraries are over
30MB in size.

This patch reverts the separation and merges LibLocale into LibUnicode
again. We now have just one library that includes the ICU data.

Further, this will let LibUnicode share the locale cache that previously
would only exist in LibLocale.

Userland/Libraries/LibUnicode/PluralRules.cpp

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2022-2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibUnicode/PluralRules.h>
+
+namespace Unicode {
+
+PluralForm plural_form_from_string(StringView plural_form)
+{
+    if (plural_form == "cardinal"sv)
+        return PluralForm::Cardinal;
+    if (plural_form == "ordinal"sv)
+        return PluralForm::Ordinal;
+    VERIFY_NOT_REACHED();
+}
+
+StringView plural_form_to_string(PluralForm plural_form)
+{
+    switch (plural_form) {
+    case PluralForm::Cardinal:
+        return "cardinal"sv;
+    case PluralForm::Ordinal:
+        return "ordinal"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+PluralCategory plural_category_from_string(StringView category)
+{
+    if (category == "other"sv)
+        return PluralCategory::Other;
+    if (category == "zero"sv)
+        return PluralCategory::Zero;
+    if (category == "one"sv)
+        return PluralCategory::One;
+    if (category == "two"sv)
+        return PluralCategory::Two;
+    if (category == "few"sv)
+        return PluralCategory::Few;
+    if (category == "many"sv)
+        return PluralCategory::Many;
+    if (category == "0"sv)
+        return PluralCategory::ExactlyZero;
+    if (category == "1"sv)
+        return PluralCategory::ExactlyOne;
+    VERIFY_NOT_REACHED();
+}
+
+StringView plural_category_to_string(PluralCategory category)
+{
+    switch (category) {
+    case PluralCategory::Other:
+        return "other"sv;
+    case PluralCategory::Zero:
+        return "zero"sv;
+    case PluralCategory::One:
+        return "one"sv;
+    case PluralCategory::Two:
+        return "two"sv;
+    case PluralCategory::Few:
+        return "few"sv;
+    case PluralCategory::Many:
+        return "many"sv;
+    case PluralCategory::ExactlyZero:
+        return "0"sv;
+    case PluralCategory::ExactlyOne:
+        return "1"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+}