[PROP]: Make @akkadu/validator our default frontend validator

[TNieminen]

Is your feature request related to a problem? Please describe. We have decided to use validate.js in the past for all frontend request validation, but it is not documented anywhere. in addition after that decision we've extended it's features inside @akkadu/validator to which we can add extra functionality when needed.

Describe the solution you'd like

• Start using @akkadu/validator as our front-end validator
• Write documentation with examples and links to validate.js inside the module, and link to this in the style guide

[HoukasaurusRex]

So this is basically validate.js with some extensions? That sounds fine, I would say the README should be fleshed out a bit more in terms of what this is for and how to use it (probably linking to validate.js docs since that's the core module we're extending) and then in the styleguide mentioning situations where it's necessary and maybe even what should and shouldn't be validated