Add support for Force Bold Text

This CL:
1) Saves the original unbolded typeface and returns this in
getTypeface
2) Sets Paint's typeface to a bolded one if the Setting is enabled,
or a config value is YES
3)  Bolds by adding 300 to the current font weight (400 is normal,
700 is considered bold, weight is capped at 1000)
4) Resets the Paint typeface to the original value if the Setting
is disabled, or the config value is not YES

Bug: b/110991537
Test: manual; unit tests
Change-Id: If21190fd5ad9d2e1721ffe464945f00ff20f62c6