Feat/azure_ekm_proxy_api_version=0.1-preview

[HatemMn]

Issue #653

Overview :

Basically an implementation of Azure EKM API as following in a loyal manner the specifications. This is version 0.1-preview, the code is flexible for future versions

What's done :

• Added the necessary configs as well as the possibility to enable/disable azure EKM
• Implemented the info / get metadata / Wrap / unwrap endpoints like specified
• created all specified error responses, despite some of them being currently un-used
• authentification ( mTLS )
• Tests

What's TBH :

• the "1. Prerequisites" ( read page 6)
• the timeout, they said it should be 250ms max

⚠️ Information if someone takes over development :

• Be careful about the multiple edge cases that could arise because some of the parameters the API asks for are set as Option<...> in the KMS. These cases should be addressed case by case, check the metadata endpoint
• AzureEKMReply (in error.rs) is not an error but a struct that converts to a HTTP response. Read error.rs, eveything has been done for auto conversions toward whatever the API asks, try to leverage that. If what I am saying is not clear read the get metadata endpoint
• A TODO file has been places in google_cse, for some suggestions that has nothing to do with azure EKM api
• A contributing.md file has been added too
• Consider moving the handlers to a file like operations.rs or handlers.rs ?
• please Ctrl+Maj+F over "TODO(review)" keyword and reply to the questions that I am not sure about since the spec does not say anything

Closes #653

[HatemMn]

Needs a rebase

Otherwise this will stop at this stage until an azure prod env is available to test

[Manuthor]

Needs a rebase

Otherwise this will stop at this stage until an azure prod env is available to test

I believe you can rebase from now since #658 has been merged to develop

[HatemMn]

Just rebased