Serlo Editor - v0.19.1

• fix(editor): remove fixed size from text area icon. Thank you @LarsTheGlidingSquirrel in #4303
• fix(editor): allow state to be undefined/null in SerloRenderer. Thank you @LarsTheGlidingSquirrel in #4302
• refactor(editor): normalize links only on serlo.org. Thank you @elbotho in #4301
• fix(plugin-edusharing): allow focusing the plugin by clicking on the content. Thank you @LarsTheGlidingSquirrel in #4298
• chore: upgrade math packages and graphql-request. Thank you @elbotho in #4290
• fix(link-plugin): Allow absolute serlo urls in integrations. Thank you @CodingDive in #4289
• chore: upgrade redux etc. Thank you @elbotho in #4288
• chore: upgrade typescript version, bump target to es2018. Thank you @elbotho in #4286
• chore: upgrade react dom and misc. Thank you @elbotho in #4284
• chore: upgrade prettier. Thank you @elbotho in #4283
• chore: upgrade next & misc packages. Thank you @elbotho in #4282
• Add icon for text area exercise (frei text plugin). Thank you @CodingDive in #4276
• Revert "chore(deps): bump @radix-ui/react-navigation-menu from 1.1.4 to 1.2.1". Thank you @elbotho in #4272
• chore(deps): bump @radix-ui/react-navigation-menu from 1.1.4 to 1.2.1. Thank you @dependabot[bot] in #4266
• chore(deps): bump clsx from 2.1.0 to 2.1.1. Thank you @dependabot[bot] in #4265
• refactor(editor): remove upload tagging code. Thank you @elbotho in #4260
• refactor(editor): adapt variable name from imgSrc to fileUrl. Thank you @elbotho in #4259
• fix(plugin-edusharing): fix visual errors in embeds. Thank you @LarsTheGlidingSquirrel in #4258
• refactor(editor): adapt upload code to changes on server, get parent host for usage in iframe. Thank you @elbotho in #4257
• fix(editor): commit temporary actions to history only after resolving them. Thank you @hejtful in #4252
• feat(editor): add user id to image upload. Thank you @elbotho in #4251
• fix(editor): adapt image proxy rule. Thank you @elbotho in #4250
• chore: migrate eslint to use new config format. Thank you @elbotho in #4249
• Production. Thank you @elbotho in #4245
• Deploy: fix(editor): update injection url for production. Thank you @elbotho in #4244
• Deployment. Thank you @elbotho in #4243
• refactor: move some tailwind theme stuff to frontend. Thank you @elbotho in #4240
• refactor(edusharing-asset): replace react-modal. Thank you @elbotho in #4239
• refactor(editor): add image proxy for privacy (serlo-only). Thank you @elbotho in #4224

Full Changelog: v0.19.0-editor...v0.19.1-editor