[IMP] product: specify a view for 'Variant Values' action
[FIX]Used bom.bom_line_ids instead of sbom.bom_line_ids,search boms on product ids of bom component,and browse record outside of if condition to, fix traceback when click on Recompute Price from Bom button in product variant form view

[FIX] Removed cost method field from product template form view to fix duplication of this field.

[REV] Revert changes for duplication of cost method bcoz it is fixed in master.

[IMP]Removed code for search bom base on product and removed prod_set used product_ids for compute cost price.