Optimize Memory and Performance in waveform.js

[mplawner]

This pull request introduces a series of optimizations aimed at improving the performance and memory usage of the waveform.js file. The changes focus on pre-allocating arrays where possible, optimizing array manipulations, and replacing library-specific methods with native JavaScript alternatives where appropriate.

Key Changes:

• Pre-allocated the samples array as a Float64Array to reduce dynamic memory allocations.
• Introduced sampleCount to keep track of the number of samples, allowing us to trim the pre-allocated samples array to its actual size.
• Replaced the non-existent d3.maxIndex function with native JavaScript code to find the index of the maximum RMS value.

These changes aim to enhance the performance and reduce the memory footprint of the getWaveform function, especially when working with large audio files.

Please review and test these changes thoroughly to ensure they meet all functional and performance requirements.

[TworkC]

Do you have this building successfully locally or through docker? I've been running into issues with the original branch on Docker.