Support different kinds of rewards

[Tibesnoff]

Description
Currently, the front-end and back-end only support rewards with fixed percentages. (Even tho the backend can handle variable percentages). We want to be able to hold many rewards that may change monthly or yearly or could include spending limits. It would also be able to hold other types of rewards such as flying miles on airlines

Acceptance Criteria

• Add new types of rewards
• Sorting functions in the front-end to show the best cards to use need to support this change. Currently, they only show by best percent.

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