fix(repository): Move backend code into subdirectory

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

.github/workflows/e2e-tests.yml

@@ -1,86 +0,0 @@
-# SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
-#
-# SPDX-License-Identifier: AGPL-3.0-only
-
-name: E2E Tests
-
-on:
-  push:
-    branches: [ develop ]
-  pull_request:
-    branches: [ develop ]
-
-env:
-  NODEJS_VERSION: 18
-
-
-jobs:
-  sqlite: # This run also collects coverage
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-      - name: Use Node.js ${{ env.NODEJS_VERSION }}
-        uses: actions/setup-node@v3
-        with:
-          node-version: ${{ env.NODEJS_VERSION }}
-          cache: 'yarn'
-      - run: yarn install --immutable
-      - run: yarn run test:e2e:cov
-      - uses: codecov/codecov-action@v3
-        with:
-          directory: coverage-e2e
-          flags: e2e-tests
-
-  mariadb:
-    runs-on: ubuntu-latest
-    services:
-      mariadb:
-        image: mariadb
-        env:
-          MYSQL_USER: hedgedoc
-          MYSQL_PASSWORD: hedgedoc
-          MYSQL_DATABASE: hedgedoc
-          MYSQL_ROOT_PASSWORD: hedgedoc
-        options: --health-cmd "mysqladmin ping" --health-interval 5s --health-timeout 2s --health-retries 5
-        ports:
-          - 3306:3306
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-      - name: Use Node.js ${{ env.NODEJS_VERSION }}
-        uses: actions/setup-node@v3
-        with:
-          node-version: ${{ env.NODEJS_VERSION }}
-          cache: 'yarn'
-      - run: yarn install --immutable
-      - run: yarn run test:e2e
-        env:
-          HEDGEDOC_TEST_DB_TYPE: mariadb
-
-  postgres:
-    runs-on: ubuntu-latest
-    services:
-      postgres:
-        image: postgres
-        env:
-          POSTGRES_PASSWORD: hedgedoc
-          POSTGRES_USER: hedgedoc
-        options: --health-cmd pg_isready --health-interval 5s --health-timeout 2s --health-retries 5
-        ports:
-          - 5432:5432
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-      - name: Use Node.js ${{ env.NODEJS_VERSION }}
-        uses: actions/setup-node@v3
-        with:
-          node-version: ${{ env.NODEJS_VERSION }}
-          cache: 'yarn'
-      - run: yarn install --immutable
-      - run: yarn run test:e2e
-        env:
-          HEDGEDOC_TEST_DB_TYPE: postgres