Added Dapr Crypto .NET Quickstart

[WhitWaldo]

Description

Added quickstart demonstrating the use of the Dapr Crypto API showing encryption and decryption for both strings and file streams.

Issue reference

N/A - part of 1.15 endgame

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• The quickstart code compiles correctly
• You've tested new builds of the quickstart if you changed quickstart code
• You've updated the quickstart's README if necessary
• If you have changed the steps for a quickstart be sure that you have updated the automated validation accordingly. All of our quickstarts have annotations that allow them to be executed automatically as code. For more information see mechanical-markdown. For user guide with examples see Examples.

[alicejgibbons]

Thanks @WhitWaldo!! Same comments on this one:

• remove the python sdk commits,
• sign your commits
• Ensure similarity with the other crypto quickstarts

[WhitWaldo]

Thanks @WhitWaldo!! Same comments on this one:

* remove the python sdk commits,

* sign your commits

* Ensure similarity with the other crypto quickstarts

Same issue as the other - the python commit showed up when I targeted dapr:release-1.15 as it's not on my local branch. Again, should I be targeting a different branch to merge into?

I didn't realize I missed a commit. I'll circle back on that one.

This is the one project I actually read the other quickstarts and I didn't like them as much so I went in another direction. Why would anyone encrypt an image? It made more sense to me to offer practical examples that demonstrated several different techniques offered by the SDK:

• Encryption of a string value
• Encryption of a file-based stream
• Encryption of an in-memory stream

I also considered adding a large-file version generated at runtime (so as not to add to the tree) that demonstrates the bidirectional streaming capability inherent to the SDK (not as easily done with HTTP) as it's been an ask several times for support greater than 4 GB.