Adding support for variables in conversation

[rahul101001000]

Description

Often one needs to reference previous answers or data as part of the questions in the current conversation. These answers/data may come from 3 sources -

1. Registration data
2. Attributes derived from previous answers in same conversation
3. Attributes from other conversations

Why

Use case 1: Variables from user registration data e.g. name, email
'Hi $NAME$'

Use case 2: Attributes from previous answers in same conversation
'In the last question, you said $ATTRIBUTE_AESTHETICS$ in conversation

Use case 3: Attributes from previous conversations
'You would like to become $ATTRIBUTE_DESIRED_OCCUPATION$'

Implementation wise 2 and 3 may be the same

Alternatives

We will need to skip any references to previous answers in the conversation. That will make the conversations less personable and natural.