Update 'Initial Soil Conditions' subsection of the 'Soil Parameters' section of the user guide

[soaressgabriel]

Checklist:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Added tests for changed code.
• Updated documentation for changed code.

Description

• Updates the following parts of the User Guide > Soil Parameters > Initial Soil Conditions:
  • Initial Baseflow: added equation used in this calculation, more information and new example value;
  • Baseflow Threshold: added equation used in this calculation, more information and new example value;
  • Initial Saturated Zone Storage: added alert about the generation of baseflow in the initial step.
• Adds links to related parts of the documentation.

Related Issue

• Resolve Update 'Initial Soil Conditions' subsection of the 'Soil Parameters' section of the user guide #87.

Motivation and Context

• See Description and Context of Update 'Initial Soil Conditions' subsection of the 'Soil Parameters' section of the user guide #87.

How Has This Been Tested

N/A