Added Depreciation Percentage as an option

[Godmartinz]

Description

This adds the ability to calculate depreciations by percentage. which takes the purchase cost and grabs the percentage and substitutes it in for the amount. the current formula has not changed. this just adds a private method calculateDepreciation() to handle this math.

A percentage option has been added to Depreciations:

Floor Value as an amount or percentage:

Error if you go outside of 0-100%:

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• PHP version:
• MySQL version
• Webserver version
• OS version

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[what-the-diff]

PR Summary

• Addition of 'Depreciation Type' Column
  A new column called depreciation_type has been added to the depreciations table.

• Updates in Depreciations Controller
  The DepreciationsController.php file has been updated to include the depreciation_type field. This includes operations where a new depreciation record is created (store method) and instances where a depreciation record is updated (update method). It also includes adding validation rules for depreciation_min and depreciation_type fields.

• Validation of 'Depreciation Type' field
  New validation rules have been set for the depreciation_type field. It can only accept the values 'amount' or 'percent'.

• Updates in Depreciation Transformer
  The transformer class DepreciationsTransformer.php has been updated to handle the transform operation related to depreciation_min.

• Modification in Depreciable Model
  The Depreciable.php model file has a new method calculateDepreciation() that calculates depreciation based on the minimum depreciation and the depreciation type. This new method is now used in the getLinearDepreciatedValue and getMonthlyDepreciation methods.

• Updates in API Depreciation Controller
  The Api/DepreciationsController.php file now allows 'depreciation_type' in the list of fields ($allowed_columns) and hence it is included in the select query.

• Updates in View File
  A select input field for depreciation_type has been added to the depreciations/edit.blade.php view file.

[snipe]

This looks great - can you add in a test or two here as well?

[akemidx]

This looks good! Math seems solid and the now() variable seems to be fine for what we wanna do.

[Godmartinz]

@snipe added a test for amount and percentage 👍