BC-8147 - Upgrade to ESLint 9

[NFriedo]

Short Description

In Eslint 9, there is a new default config format system, the flat config. Its also possible to use the new format in Eslint v8 (current: eslintrc format).
We want try to use the flat config and see if there are any problems.

This PR will upgrade ESLint 8 to ESLint 9.

Links to Ticket and related Pull-Requests

BC-8147

Changes

• change eslintrc format to flat config
• add configType: "flat" option to ESLintWebpackPlugin in webpack.common.js
  • ⚠️ Attention: as long as we use eslint 8, we need to add eslintPath: "eslint/use-at-your-own-risk", this is experimental
  • eslint 9 support is already there for the eslint webpack plugin
• just @vue/eslint-config-typescript is not supporting the new format yet:
  • so we need to use the compatibility utilities FlatCompat from @eslint/eslintrc
  • they already working on v14, where they add support for flat config
• we don't need to add our custom eslint plugin to the package.json anymore
• remove .eslint.ignore (no longer supported), moved to ignores config object in eslint.config.js

Commits 7.10.24:

• upgrade @vue/eslint-config-typescript to version 14
• upgrade to eslint 9.12.0
• set "@typescript-eslint/no-unused-vars": "warn", because there are many eslint errors in catch block
  • need to decide if want to use default option caughtErrors: all for 'catch' blocks
• disable "no-unused-vars for @typescript-eslint/no-unused-vars
• set "@typescript-eslint/no-empty-object-type": ["error", { allowInterfaces: "with-single-extends" },],
• set "@typescript-eslint/no-require-imports": "off" for now
• remove eslintPath: "eslint/use-at-your-own-risk" because this was just needed vor eslint 8
• fix eslint errors

Data-security

Deployment

New Repos, NPM packages or vendor scripts

Screenshots of UI changes

Checklist before merging

• QA: In addition to review, the code has been manually tested (if manual testing is possible)
• PO: Any deviation from requirements was agreed with Product-Owner / ticket author / support-team
• DEV: Every new component is implemented having accessibility in mind (e.g. aria-label, role property)

Notice: Please keep this Pull-Request as a Draft (or add WIP label), until it is ready to be reviewed

[sonarqubecloud]

Quality Gate failed

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud