feat: add translations and locale to landing

[spaenleh]

In this PR:

• setup a plug to handle locale from http and session
• add a component that allows to change language via a dropdown
• translate page footer and menus
• upgrade daisyui.js and daisyui-theme.js (should probably be broken out to a different PR)
• add a /locale debug page to see which locale is in use and what are the values from the headers and from the session. It allows to change locale and remove locale.

ref #131

Still to do:

Translate the page texts, this poses a challenge since we have a lot of bolded text in there... We can:

• add tags to the translations and display the values with raw but not very safe and could easily be lost in the translations or have bugs where part of the tag is missing.
• remove most of the highlights and where they are absolutely necessary, make custom bits of text (ugly and adds translations that lack context)
• something else ?

[pyphilia]

Thanks for this PR! I think you will update again so I can review again after 🍽️