Upgrade Next.js and to remove the openssl workaround

[thomvaill]

We are running Next.js v10, while the current latest major version available is v14.

Next.js v10 runs Webpack 4, which uses a deprecated openssl hashing algorithm (md4) (#85).
A workaround was introduced:

• fix: workaround for ERR_OSSL_EVP_UNSUPPORTED build issue #114
• then Make Log4brains run on Node 18 and 20 #124
• and fixed by fix: lerna publish on Node 18-20 #125

But we should try to upgrade ASAP to get rid of this workaround.

Since we rely a lot on Next.js hacks (#NEXTJS-HACK comments in the code), the task does not look easy at all. Let's first assess if we should target to latest version, or a closer one, like v11 which introduces Webpack 5.

[thomvaill]

Blocks #4 since it may change the images behaviour