[harfbuzz] Add shared_library target, plus FreeType integration

A shared library target enables the use of Rust crates that wrap harfbuzz.

Also, add hb-ft.{cc,h} to library (HarfBuzz-FreeType integrations), along with
the corresponding FreeType dependency.

TEXT-60 #comment

Change-Id: I35b4d5827a4c69b0756da4304caaff96a361f8ec
1 file changed