Programming Task Assignment: Time travel visualizer

[ignaciabaeza]

Changes in this PR:

• Add lazy loading by creating /getNeighborsForSample endpoint to load neighbors and projections for only one point at a time
• Add parallel loading of epochs in batches so its faster. batch size defined in a .env, 5 by default
• Enhance visualization by adding collapse and draggable blocks on sidebar
• Add a loading overlay to visualization
• Add a benchmark script to compare loading time between old and new implementation
• Minor css changes (padding, background colors, etc)
• Added a README in the docs/ folder to explain in more detail every change

Everything should work as expected and be faster than before.