base: Introduce FontService

In addition to shipping with a series of fonts, this service
also supports user apps that provide fonts. To create a font
provider app, put the following bool into your package resources

<bool name="custom_rom_font_provider">true</bool>

Then put the font zips into

/res/assets/fonts/font1.zip... font2.zip...

At a later time, other font sources may be supported, but this
is not certain.

Change-Id: Ie3b4e3e740956f34b0ffb45c4632c2f62f26f48a
Signed-off-by: Jackeagle <jackeagle102@gmail.com>
11 files changed