0.10 release notes (#2352)

* 0.10 release notes

This PR proposes the addition of the 0.10.0 release notes to the Boundary Docs page

* update nav structure to include 0.10.0

* Update v0_10_0.mdx

Added link to HCPb Credential Injection Tutorial

website/content/docs/release-notes/v0_10_0.mdx

@@ -0,0 +1,51 @@
+---
+layout: docs
+page_title: v0.10.0
+description: |-
+  Boundary release notes for v0.10.0
+---
+
+# [Boundary v0.10.0](https://www.boundaryproject.io/downloads)
+
+The release notes below contain information about new functionality available in the Boundary v0.10.0 release.
+To see a granular record of when each item was merged into the Boundary project, please refer to the [Changelog](https://github.com/hashicorp/boundary/blob/main/CHANGELOG.md).
+To learn about what Boundary consists of, we highly recommend you start at the [Getting Started Page](/docs/getting-started).
+
+Lastly, for instructions on how to upgrade an existing Boundary deployment to v0.10.0, please review Boundary's [general upgrade guide](https://learn.hashicorp.com/tutorials/boundary/upgrade-version).
+
+## Boundary v0.10.0 Highlights
+
+**Credential Management of SSH Keys:** Boundary 0.10 includes enhancements to credential management, including added support for management of SSH private keys.
+
+
+**SSH Brokering Helper Function:** We’ve expanded support for the SSH brokering helper function that allows users to seamlessly connect to machines remotely 
+without having to manually enter their brokered credentials. 
+
+**Enhanced IAM Workflows in the Boundary Admin UI:** Boundary 0.10 introduces enhanced IAM associations to Boundary’s Admin UI, allowing users to expand IAM associations in a 
+project scope to resources such as group members and principals that reside in other scopes.
+
+**SSH Credential Injection via Password and Public Key Authentication:** HCP Boundary now supports SSH Credential Injection, an active method of injecting credentials into an 
+established connection, so that credentials are never exposed to users. [Learn more here](https://learn.hashicorp.com/tutorials/boundary/hcp-ssh-cred-injection?in=boundary/hcp-administration).
+
+
+
+
+## What's Changed
+* `ssh` Target Type With Credential Injection (HCP Boundary only): Boundary has
+  gained a new `ssh` target type. Using this type, username/password or SSH
+  private key credentials can be sourced from `vault` credential libraries or
+  `static` credentials and injected into the SSH session between a client and
+  end host. This allows users to securely SSH to remote hosts while never being
+  in possession of a valid credential for that target host.
+* SSH Private Key Credentials: There is now an `ssh_private_key` credential type
+  that allows submitting a username/private key (and optional passphrase) to
+  Boundary for use with credential injection or brokering workflows.
+* `boundary connect ssh` Credential Brokering Enhancements: we have extended
+  support into the `boundary connect ssh` helper for brokered credentials of
+  `ssh_private_key` type; the command will automatically pass the credentials to
+  the `ssh` process ([PR](https://github.com/hashicorp/boundary/pull/2267)).
+* `boundary authenticate`, `boundary accounts`: Enables use of `env://` and
+  `file://` syntax to specify location of a password
+
+
+**For more detailed information of all changes since 0.9.0, please refer to the [Changelog](https://github.com/hashicorp/boundary/blob/main/CHANGELOG.md)**

website/data/docs-nav-data.json

@@ -466,6 +466,10 @@
         "title": "Overview",
         "path": "release-notes"
       },
+      {
+        "title": "v0.10.0",
+        "path": "release-notes/v0_10_0"
+      },
       {
         "title": "v0.9.0",
         "path": "release-notes/v0_9_0"