Overhaul frontend to utilize an SPA framework

[Gawdl3y]

Although Tracker's backend was almost entirely rewritten last year, the frontend has mostly been carried over with only minor improvements and mostly changes made to accommodate the new backend. While certainly not a small task, rebuilding the frontend to take advantage of a modern SPA JavaScript framework (likely Vue 3) would dramatically improve the future maintainability and extensibility of the application, making it much easier to build on and work with for both current and future contributors. This would also serve as a platform for much more dramatic frontend features and changes that were previously difficult to implement. SPA design in particular suits Tracker very well given its very real-time and fairly compact nature.

[Gawdl3y]

The groundwork for this has been done in #24.

[Gawdl3y]

Work on this is continuing in the frontend-2.0 branch.