Electron 12 + Refactor module system

[leohubert]

Progression:

• [x] Electron 12
• [x] Main TypeScript
• [x] Move the theme module into backend
• [x] Move dialogues into backend
• [x] Move the Module system into backend
• [x] Refactor downloaders management and processes

[iWirk]

Wesh, le build Ubuntu fail XD je te laisse corriger ça et re-request la review 😊

[leohubert]

Et voilà chef @iWirk