Migrates from TSLint to ESLint (#12)

Author: rhermes62

.eslintrc

@@ -0,0 +1,31 @@
+{
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "project": "./tsconfig.eslint.json"
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/eslint-recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:@typescript-eslint/recommended-requiring-type-checking",
+    "prettier",
+    "prettier/@typescript-eslint"
+  ],
+  "rules": {
+    "@typescript-eslint/interface-name-prefix": "off"
+  },
+  // Be more lenient in tests for some rules
+  "overrides": [
+    {
+      "files": ["./test/**/*", "**/__tests__/*"],
+      "rules": {
+        "@typescript-eslint/ban-ts-ignore": "off",
+        "@typescript-eslint/explicit-function-return-type": "off",
+        "@typescript-eslint/no-explicit-any": "off",
+        "@typescript-eslint/no-non-null-assertion": "off",
+        "@typescript-eslint/no-use-before-define": "off",
+        "@typescript-eslint/unbound-method": "off"
+      }
+    }
+  ]
+}