feat: Item Tax Templates for Germany

[barredterra]

• Item Tax Templates for Germany

  Before:

  • One Sales Taxes and Charges Templates for each VAT rate: "VAT 19%", "VAT 7%", etc..
  • There were no Item Tax Templates and it would be useless to create them in this structure.
  • You could only select one template, and therefore tax rate, per transaction.
  • Tax Category could only be assigned to only one of the templates, despite all belonging to the same category.

  After:

  • One generic Sales Taxes and Charges Template "VAT" with multiple Accounts at a default rate of 0.00.
  • Item Tax Templates for each tax rate are used to apply the correct rate. This way, Items with different tax rates can be sold in a single transaction.

• Validate that the provided Company exists before running taxes setup

• Create Tax Category during taxes setup

  If tax_category is specified in country_wise_tax.json, make sure the Tax Category exists before creating a Tax Template.

• port to develop.

no-docs

[coveralls]

Coverage increased (+0.003%) to 61.198% when pulling 5079440 on alyf-de:item-tax-templates into 04dfaf3 on frappe:version-13-hotfix.

[deepeshgarg007]

@barredterra Have done something similar for India in this PR #25415

I am creating Tax Categories separately as there are a few custom fields for India and then assigning them to templates.
Any thoughts on this?

[barredterra]

@deepeshgarg007 I refactored the Tax Category setup similar to your PR: f259bf4. I think this should also work for your use case.

[barredterra]

@deepeshgarg007 could you review this PR first, then rebase yours?

[deepeshgarg007]

@barredterra this looks fine, hence merging this. Will rebase mine