inexpensive homepage

[onlyphantom]

This commit include a handful of changes, and is part of a larger, more drastic effort to re-write the app's more expensive functionalities (db read/write operations, other type of IO etc). Home page no longer uses any global object to render information, which reduces the need for db operations apart from the authentication phase.

Other benefits:

• This should also have the added advantage of making the app experience feels snappier
• Caching is more straightforward, since we can cache the entire "view", which includes global stats but don't require current user information

Other features / enhancements:

• Handful of UX / UI decisions (ref: Font Color in Plot #11, Grid line color in major x-axis #15, Grid line in x and y axis in accomplishment tab #16) - plot looks cleaner as a result