Ecthelion 1.1+ features and improvements

[retrixe]

Code improvements:

• enable more ESLint rules
• drop inline styling where it's become big
• many memoised components don't need to be
• config option to enable cookie authentication

UX improvements:

• add file to routes
• allow uploading files and doing file explorer actions simultaneously
• improve request errors in dashboard pages (e.g. proper 404 when folder doesn't exist)
• #24

Features:

• future: enhanced file editor
• fix Shift+Click in files explorer
• low priority: highly customisable UI
• stacked overlay for simultaneous multi-upload and mass actions