feat(servers content): file upload + extra mod info + misc

[he3als]

New

• Adds drag & drop upload support for mod and plugin files on the content page
  • Reuses the file upload status from the file manager
  • Adds a button to upload files as well
• @ferothefox Add extra info (file name, author) to each mod
• @ferothefox Show number of mods in search box
• Adds a "No mods/plugins found for your query!" message if nothing is found, with a button to show everything again

Fixes

• @ferothefox Tweak button styles
• Only scroll to the top of the mod/plugin list when searching if already scrolled down
• Tweak content page mobile UI