Dynamically load components + scripts

[lynkos]

Use event listeners to dynamically load relevant content for components, excluding iTerm since it's the only auto-visible component/window.

E.g. ONLY load HTML + JavaScript for calculator when calculator icon is clicked. And the loading should only be done on the 1st click, so there's no redundant loading if user decides to open, close, and reopen calculator.

• Menubar dropdown content (onclick)
• Context menu (onrightclick)
• Calculator (onclick for launchpad icon)
• TextEdit (onclick for dock, desktop, + launchpad icons)
• Mail form (onclick for dock + launchpad icons)
• Notes (onclick for dock + launchpad icons)
• Browser (onclick for dock + launchpad icons)
• Preview window (onclick for desktop icon)
• Resume window (onclick for desktop icon)
• Launchpad (onclick for dock icon)
• Trash dialogue (onclick for dock icon)
• Rainbow loader (only load during/after mail message is sent)
• Relevant JavaScript files (e.g. script importing calculator script)