chore(eslint): streamline configs into flat config file (#569)

eslintrc configs are [deprecated with
eslint@9^](https://eslint.org/docs/latest/use/configure/configuration-files-deprecated)
instead, [flat config files are
used](https://eslint.org/docs/latest/use/configure/configuration-files)

needed for #566

eslint.config.js

@@ -0,0 +1,62 @@
+'use strict'
+
+const eslint_js = require('@eslint/js')
+const eslint_ts = require('@typescript-eslint/eslint-plugin')
+const typescript_parser = require('@typescript-eslint/parser')
+const globals = require('globals')
+
+module.exports = [
+  // global rules for all files
+  eslint_js.configs.recommended,
+  // Generic config for JavaScript files: Setup environment, version, etc.
+  {
+    files: ['**/*.js'],
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'commonjs',
+      globals: {
+        ...globals.node,
+        ...globals.jest,
+        ...globals.es6,
+        SELECT: true,
+        INSERT: true,
+        UPSERT: true,
+        UPDATE: true,
+        DELETE: true,
+        CREATE: true,
+        DROP: true,
+        CDL: true,
+        CQL: true,
+        CXL: true,
+      },
+    },
+    rules: {
+      'no-extra-semi': 'off',
+      'no-unused-vars': ['warn', { argsIgnorePattern: 'lazy' }],
+      'no-console': 'error',
+    },
+  },
+  {
+    files: ['**/*.ts'],
+    plugins: {
+      '@typescript-eslint': eslint_ts,
+    },
+    languageOptions: {
+      parser: typescript_parser,
+      globals: {
+        ...globals.node,
+      },
+    },
+    rules: {
+      ...eslint_ts.configs.recommended.rules,
+      '@typescript-eslint/no-unused-vars': ['warn'],
+      '@typescript-eslint/no-explicit-any': ['warn'],
+    },
+  },
+  {
+    files: ['**/hana/**/*.js'],
+    rules: {
+      'no-console': 'warn',
+    },
+  },
+]