docs: Add .Net caching to docs

[novakzaballa]

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Changes

Add content about .Net caching to docs

How did you test this code?

Tested locally running docusaurus

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Name	Status	Preview	Comments	Updated (UTC)
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[matthewelwell]

I actually don't think the .NET caching implementation is usable in it's current state since it doesn't implement any method for maintaining the size. This will likely cause a memory leak in any of our customer's applications that utilise the caching and have a large number of identities. See issue here.

[novakzaballa]

I agree, we also should allow the user to set the TTL.

[novakzaballa]

As per the conversation, this docs PR will be closed until the feature is complete.