Remove hardhat-foundry and check harnesses compilation in CI (#4832)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

hardhat/remappings.js

@@ -0,0 +1,18 @@
+const fs = require('fs');
+const { task } = require('hardhat/config');
+const { TASK_COMPILE_GET_REMAPPINGS } = require('hardhat/builtin-tasks/task-names');
+
+task(TASK_COMPILE_GET_REMAPPINGS).setAction((taskArgs, env, runSuper) =>
+  runSuper().then(remappings =>
+    Object.assign(
+      remappings,
+      Object.fromEntries(
+        fs
+          .readFileSync('remappings.txt', 'utf-8')
+          .split('\n')
+          .filter(Boolean)
+          .map(line => line.trim().split('=')),
+      ),
+    ),
+  ),
+);