NTP initial render is slowed down due to large bundle size

[petemill]

Description

New Tab Page's JS bundle is a single 1.34mb file. This takes time to parse before the initial render happens.
Seems like most of it is taken up by css and fonts which is not necessary for the initial JS to run.

Steps to Reproduce

From src/brave, run:

DEPFILE_PATH=$TMPDIR/brave-temp-depfile-webpack DEPFILE_SOURCE_NAME=wtf npm run web-ui -- --mode=production brave_new_tab_ui=$PWD/components/brave_new_tab_ui/brave_new_tab.tsx --progress

Actual result:

1340mb

Expected result:

<500k

Reproduces how often:

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the dev channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information: