Caching across pods for Altinn Apps

## Description
Currently, we do not have support for caching data across pods for an app.
If autoscaling is introduces or replica count is inreaced we can have multiple instances of an app running in the cluster.
how can we support caching across multiple instances of an app?

## In scope
> What's in scope of this analysis?

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## Out of scope
> What's **out** of scope for this analysis?

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## Constraints
> Constraints or requirements (technical or functional) that affects this analysis.

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## Analysis

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## Conclusion
> Short summary of the proposed solution.

## Tasks
- [ ] Is this issue labeled with a correct area label?
- [ ] QA has been done

The issue names no files, tests, or entry points. Start by filling in the scope, constraints, analysis, and conclusion for caching across multiple app pods; done means the analysis has a defined scope and a documented proposed direction, with QA and area labeling addressed.

Written by the indexing model from the issue text.