Using multer options for CRUD operations on admin UI fields

[frederik]

Currently it is not possible to save texts fields in the admin UI that exceed the default multer limit of 1mb.

Description of changes

To set custom multer options it is currently necessary to set 'handle uploads' to true and define an object with the key 'multer options'.

'multer options': { dest: tmpdir(), limits: { fieldSize: 25 * 1024 * 1024 //25 mb } }, 'handle uploads': true,

These options are currently being applied during the setup of body-parser (server/bindBodyParser.js).

This pull request would also apply the options in the dynamic router (admin/server/app/createDynamicRouter.js) where multer is being used to process updates to fields in the admin UI.

Related issues (if any)

#4843

Testing

(!) WIP currently eslint fails with 291 problems (291 errors, 0 warnings) on my MacOS setup.

• List browser version(s) any admin UI changes were tested in:
• Please confirm you've added (or verified) test coverage for this change.
• Please confirm npm run test-all ran successfully.