migrate SDKs to `azure_core::error::Error`

[cataggar]

Three months ago, in late February, #625 was merged. It added azure_core::error::Error and migrated a few SDKs. Earlier this week, #766 was merged to migrate all of the generated services. These still need to be migrated.

• sdk/core HttpClient::execute_request2 @cataggar update execute_request2 to use error::Error instead of HttpError #779
• sdk/identity @cataggar migrate azure_identity to azure_core::error::Error #781
• sdk/security_keyvault @johnbatty Migrate security_keyvault to new azure_core::error scheme #782
• sdk/data_tables @johnbatty Migrate data_tables to new azure_core::error scheme #805
• sdk/device_update @mfrw Migrate sdk/storage_blob to azure_core::error scheme #794
• sdk/iot_hub @cataggar azure_core::error::Error for azure_iot_hub #801
• sdk/storage @johnbatty Migrate storage to new azure_core::error scheme #792
• sdk/storage_blobs @rickrain Migrate sdk/storage_blob to azure_core::error scheme #794
• sdk/storage_datalake @roeap Migrate storage_datalake to azure_core::error::Error #795
• sdk/storage_queues @johnbatty Migrate storage_queues to new azure_core::error scheme #800
• sdk/messaging_servicebus @danbugs Implemented messaging_servicebus crate #770
• sdk/core remove legacy errors from azure_core #806

After that, we can remove the existing azure_core::Error & azure_core::HttpError and friends.

Migration is more tedious than difficult. A bunch of .map_error can be removed. others can be replaced with .context(ErrorKind::SomeKind, "some message". If a formatted message is useful, then something like:

HeaderValue::from_str(&self.header).with_context(
    ErrorKind::DataConversion,
    || {
        format!(
            "user agent '{}' cannot be serialized as an ascii-only HTTP header
            self.header
        )
    },
)?;

[mfrw]

@cataggar Can I give some of the task(s) a stab :)

[cataggar]

@mfrw, yes please. I'll have a PR for identity soon that we can review and may be use as an example.

[johnbatty]

I've just implemented this for security_keyvault, before noticing that it isn't on your list above!
Was this a deliberate omission?

[johnbatty]

In your example above for a formatted message, the method should be with_context(...) rather than context(...) when passing a closure.

[rickrain]

@cataggar, I'm interested in helping on the sdk/storage_blobs.

[cataggar]

@rickrain, I put your name on it.

[mfrw]

@cattaggar, let me take a stab at sdk/device_update