Add storage information to cache page

[MatthewTran22]

At the top of cache.html, lets add a section that has two fields

1. total bytes used by cache
2. total bytes still available in cache

the format should be something like
1.34 gb available (1344544453 bytes)

there should be a humanized estimate with 2 significant figures, and then the actual number of bytes next to it.

how to test

= [ ] follow the associated tutorial for how sce tv works
= [ ] run the project

• download and play a video, use VLC like the readme states to ensure a stream works
• click the sce tv title, you. should see the video cached
• use the /debug endpoint defined in server.py. are we able to see the bytes that way?
• how can we add the cache space to the html page?

as a follow up, lets try adding the storage information for each cache entry. this can be a follow-up pr after the general information is implemented.