Convert vintf_fragments into vintf_fragment module(s)

Convert vintf_fragments into vintf_fragment module(s) so those manifests
can be handled in the same way between KATI defined system image and
Soong defined system image.

Bug: 322089980
Test: aosp_cf_x86_64_phone build succeeded
Change-Id: I3fde1a7569629ea8bb7ba9a50c59062dca8c8fca
Merged-In: I3fde1a7569629ea8bb7ba9a50c59062dca8c8fca
Flag: EXEMPT Refactor Android.bp
(cherry picked from commit c5d4fe25)