feat(identity-verification): sonderformat input

[Aaron-Ritter]

This pull request focuses on improving the clarity, consistency, and accuracy of identity verification documentation across several files. The main changes include clarifying possible values for API fields, improving explanations and instructions, fixing minor typos, and ensuring consistent terminology. Also splitting and renaming existing pre-verification documentation, adding a new tutorial for phone identity pre-verification as well as api identity pre-verification, and introducing deprecation warnings for outdated features.

Changes Made

Refactor identity-verification documentation:

• Separated email pre-verification and phone pre-verification instructions into distinct sections.
• Improved document titles for consistency and clarity.
• Added a draft Troubleshooting section for common issues.

New tutorials added:

• Provided step-by-step guidance for setting up phone identity pre-verification, aligning it with email pre-verification content.
• The same for using API only to verify identities.

Deprecation notice:

• Added a deprecation warning for the legacy registration verification feature.

API Field Value Clarifications and Consistency:

• Added explicit "possible values" sections for fields like user.encryptionScheme, user.twoFactor.methods[x].method, loginIdType, existingUserStrategy, verificationStrategy, and form step/type fields in various API documentation files. This makes it clearer what values are accepted or expected for these fields and therefore follows the docs guidelines.
• Improved and clarified descriptions for several API fields, including user.email, user.encryptionScheme, and others to reduce ambiguity and improve readability.

Documentation and Terminology Improvements:

• Updated terminology to consistently refer to the "FusionAuth admin UI" instead of just "FusionAuth UI" in form-related documentation.
• Improved instructions and explanations for identity verification APIs, including clearer distinctions between verifying existing users and pre-verifying identities before user creation, and added links to relevant tutorials.

Typographical and Minor Corrections:

• Fixed minor typos and improved sentence structure in various places, such as correcting "had completed verification" to "have already completed verification" and clarifying the meaning of certain fields.
• Corrected example code snippets and markdown formatting for clarity.

Link and Reference Updates:

• Updated documentation links to remove unnecessary trailing slashes for consistency and accuracy.
• Added tutorial links for identity pre-verification use cases.

Formatting and List Consistency:

• Standardized bullet lists and step formatting to improve readability and maintain consistency throughout the documentation.