Add custom linting rules (#4132)

Co-authored-by: Francisco Giordano <fg@frang.io>
Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

solhint.config.js

@@ -0,0 +1,20 @@
+const customRules = require('./scripts/solhint-custom');
+
+const rules = [
+  'no-unused-vars',
+  'const-name-snakecase',
+  'contract-name-camelcase',
+  'event-name-camelcase',
+  'func-name-mixedcase',
+  'func-param-name-mixedcase',
+  'modifier-name-mixedcase',
+  'var-name-mixedcase',
+  'imports-on-top',
+  'no-global-import',
+  ...customRules.map(r => `openzeppelin/${r.ruleId}`),
+];
+
+module.exports = {
+  plugins: ['openzeppelin'],
+  rules: Object.fromEntries(rules.map(r => [r, 'error'])),
+};