Settings dialog

[danirod]

This PR will add a proper Settings dialog with options to modify the behaviour and appearance of the program.

Will close and fix the following issues:

• Settings page #62
• Configure redirect policy for HTTP requests #66
• Al guardar una petición se guarda junto a la versión previa #73

QA

• I am able to open the settings page by pressing Ctrl + , or the Settings option in the menu.
• I can overwrite the application theme (follow system, light, dark)
• I can set a custom font for the request and response payload panes
• I can configure a redirection policy
• I can configure the behaviour on invalid or missing TLS certificates
• The translations file has been updated.

Current state: