feat: Added check box to combine items with same BOM

[noahjacob]

Improvements

• Added a check box to let user combine items with same BOM, which makes item-wise work order creation possible.
• Created a reference table to keep track of the combined item's sales order after combined.
• On submitting work order, work order qty in sales orders are updated using the reference table.
  
• Docs

[rohitwaghchaure]

@noahjacob Check sider issue

[noahjacob]

@noahjacob Check sider issue

@rohitwaghchaure fixed

[coveralls]

Coverage increased (+0.01%) to 61.24% when pulling 73e41c0 on noahjacob:prod_plan_feat into 90f7ec8 on frappe:version-13-hotfix.