orfs_flow: support ADDITIONAL_LIBS/LEFS/GDS/FILES #974

Job	Run time
Lint Bazel files	3s
Generate configs	10s
//sram:top_mix_cts	1m 41s
open //sram:top_mix	1m 40s
tag_array_64x184_generate_abstract	9s
Smoketests	6s
Local flow - clean setup	8s
tag_array_64x184_report	8s
open tag_array_64x184	8s
lb_32x128_generate_abstract	8s
open L1MetadataArray	7s
lb_32x128_test_generate_abstract	8s
open subpackage:L1MetadataArray	1m 36s
L1MetadataArray_generate_abstract	10s
open subpackage:tag_array_64x184	1m 44s
data_2048x8_generate_abstract	9s
regfile_128x65_floorplan	12s
subpackage:L1MetadataArray_generate_abstract	1m 40s
subpackage:tag_array_64x184_generate_abstract	1m 44s
Local flow - preinstalled orfs	54s
	12m 45s

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