Add yet-another-react-lightbox package and update .gitignore to exclude node_modules

frontend/node_modules/eslint/lib/shared/severity.js

@@ -1,49 +0,0 @@
-/**
- * @fileoverview Helpers for severity values (e.g. normalizing different types).
- * @author Bryan Mishkin
- */
-
-"use strict";
-
-/**
- * Convert severity value of different types to a string.
- * @param {string|number} severity severity value
- * @throws error if severity is invalid
- * @returns {string} severity string
- */
-function normalizeSeverityToString(severity) {
-    if ([2, "2", "error"].includes(severity)) {
-        return "error";
-    }
-    if ([1, "1", "warn"].includes(severity)) {
-        return "warn";
-    }
-    if ([0, "0", "off"].includes(severity)) {
-        return "off";
-    }
-    throw new Error(`Invalid severity value: ${severity}`);
-}
-
-/**
- * Convert severity value of different types to a number.
- * @param {string|number} severity severity value
- * @throws error if severity is invalid
- * @returns {number} severity number
- */
-function normalizeSeverityToNumber(severity) {
-    if ([2, "2", "error"].includes(severity)) {
-        return 2;
-    }
-    if ([1, "1", "warn"].includes(severity)) {
-        return 1;
-    }
-    if ([0, "0", "off"].includes(severity)) {
-        return 0;
-    }
-    throw new Error(`Invalid severity value: ${severity}`);
-}
-
-module.exports = {
-    normalizeSeverityToString,
-    normalizeSeverityToNumber
-};