[FEATURE]: [Stax] Currency Unit Conversion

[Sakilmostak]

📝 Feature Description

• Each currency can be described in terms of base or minor units.
• For instance, when dealing with USD currency, the Cent is considered as the minor unit, while the Dollar is considered the base unit.
• In Hyperswitch, the amount value is expected to be always provided in minor units.
• For example: In USD, If the amount is 1 in base unit (Dollar), then it will be equivalent to 100 in minor units (Cent)
• Some of the connectors integrated require the amount to be converted to a desirable unit before being passed to them.
• We have functions to_currency_base_unit and to_currency_lower_unit in place to convert the minor unit amount to its decimal equivalent and vice versa. These conversions are handled explicitly based on the connector.

🔨 Possible Implementation

• ConnectorCommon trait have been implemented for the connector.
• This trait contains get_currency_unit method. This method needs to be implemented.
• It will define what type of conversion needs to be done during connector_router_data creation. Concurrently handle the creation of connector_router_data to be passed for the connector request body creation.
• You can check this PR for further reference refactor(connector): [Zen] Enhance currency Mapping with ConnectorCurrencyCommon Trait #2196

🔖 Note: All the changes needed should be contained within hyperswitch/crates/router/src/connector/

📦 Have you spent some time checking if this feature request has been raised before?

• I checked and didn't find a similar issue

📦 Have you read the Contributing Guidelines?

• I have read the Contributing Guidelines

✨ Are you willing to submit a PR?

[Charuhas10]

Hey can I take this issue?

[Sakilmostak]

Hello @Charuhas10, you have a issue assigned to yourself. To diversify the participants, we can assign another issue only if the contributor is done (at least reviewed) with the previous one👍

[shivansh-bhatnagar18]

Dear Authors, I would love to contribute to this issue. I have already raised a PR on a previous issue #2664 which almost has the same implementation

[deepanshu-iiitu]

Hey @shivansh-bhatnagar18 , sure! I've assigned this to you.

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