Add permanent option context var

[medtaher123]

Motivation

We need to add a flag for context variables called "permanent" boolean. Currently a context var value is only kept during the current conversation and then gets lost. It would be good to add the "permanent" option allow the value to be stored in the subscriber object in a attribute called "context" (json).

Feature desciption:

There are two types of context variables in Hexabot: non-permanent and permanent.

1. Non-Permanent Context Variables

• Temporary Storage: Non-permanent context variables are stored in the conversation context.
• Scope: They are specific to the ongoing conversation and are lost once the conversation ends. This makes them ideal for storing temporary data that is relevant only during the current interaction.
• Example: If a bot asks a user for their preferred meeting time during a session, the bot may store the response as a non-permanent context variable to use in the rest of the conversation.

2. Permanent Context Variables

• Persistent Storage: Permanent context variables are stored in the subscriber context, which means they persist across multiple conversations.
• Scope: These variables retain their values even after a conversation has ended, allowing the bot to remember information about a user across different interactions.
• Example: If a user provides a preference for a certain feature, such as opting into notifications, the bot can store this preference permanently. The bot will retain this information for future use, without needing to ask the user again in subsequent conversations.

Fixes #48

Type of change

Please delete options that are not relevant.

• 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

Checklist:

• 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 (Storybook)
• I have added unit tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[marrouchi]

Looks good @medtaher123 Thanks 👏

I think you will need to adapt the unit tests.

[medtaher123]

• Add "permanent" attribute to the context var entity
• Add "context" attribute in the subscriber entity
• Capture permanent context vars in the subscriber
• update unit tests
• Use the permanent context vars in the token replacement
• update unit tests
• add the permanent option in the frontentend contextVars page
• create a new migration

[marrouchi]

@medtaher123 Thank you 🙏 Can you please add a comment to the field permanent to explain what it does ?
Also, in the PR, add a detailed description of what a permanent context var is compared to a non permanent. Will be used in the documentation ;)