[Style] move common files of board variants into common subfolder

[boelkrug-intel]

Description

This PR removes duplicate files in the D5005 board variants ofs_d5005 and ofs_d5005_usm. All duplicates are now moved into the common/ subfolder and build-bsp.sh uses the common/ folder as skeleton to build out the board variants. Only files that are different remain in the ofs_d5005 and ofs_d5005_usm folders which are

board_spec.xml build/opencl_afu.json build/ip/board/board_afu_id_avmm_slave_0.ip build/rtl/ofs_asp.vh

Collateral (docs, reports, design examples, case IDs):

none

Tests added:

none

Tests run:

• ran build.bsp in unchanged repo and in repo with this change -> resulting board variant directories ofs_d5005 and ofs_d5005_usm are identical