Addition of **invitation letter** for manual insertion of question

[Nikronic]

Intro

For more info please see #110

Tasks

• Assignment to a XAI categorization (purpose)
• Distribution of XAI values for each response: determining a_i values for all the possible answers of each new question (variables)

# invitation_letter_indicator only takes [True, False] values
xai_invitation_letter_indicator = {
    "has_inv_True": +a_1,
    "has_inv_False": +a_2
}

• Determining the value for Vizard awareness: variables/questions covered by the model now cover %100 awareness. What should be the value of each feature when including manually?

# 1. set b = a_i where a_i is the XAI value of the answer to the question
# 2. define a `normalize` function where takes the old (all XAI) values and maps them to the range of `[0, (1-b)]`
# 3. now `awareness_new = normalize(awareness_old) + b` 

• Determining the effect on the final prediction: this is given directly, yet we have to do something similar to previous step for having a value in range of [0, 1]
• Determining the text of the question and the answer