LibreJS: Fix Table Formatting

This commit makes the LibreJS table utilize the bootstrap styles
make the table not look absurdly ugly. It also adds table headers,
which is nice 👌.

In the future, it might be neat to add a test case which loads the
LibreJS parse engine to check for licenses that are not added to the
table. Is there a way to load the IceCat addin in some kind of
headless firefox?

Signed-off-by: Mark Stenglein <mark@stengle.in>
5 jobs for 148-librejs in 3 minutes and 30 seconds
Status Job ID Name Coverage
  Test
passed #2749
Go-py2.7

00:01:35

passed #2750
Go-py3.4

00:01:37

passed #2751
Go-py3.5

00:01:37

passed #2752
Go-py3.6

00:01:38

 
  Lint
passed #2753
Go-flake8

00:01:52