feat(coderd): connect dbcrypt package implementation (#9523)

See also: https://github.com/coder/coder/pull/9522

- Adds commands `server dbcrypt {rotate,decrypt,delete}` to re-encrypt, decrypt, or delete encrypted data, respectively.
- Plumbs through dbcrypt in enterprise/coderd (including unit tests).
- Adds documentation in admin/encryption.md.

This enables dbcrypt by default, but the feature is soft-enforced on supplying external token encryption keys. Without specifying any keys, encryption/decryption is a no-op.

docs/cli/server_dbcrypt.md

@@ -0,0 +1,19 @@
+<!-- DO NOT EDIT | GENERATED CONTENT -->
+
+# server dbcrypt
+
+Manage database encryption.
+
+## Usage
+
+```console
+coder server dbcrypt
+```
+
+## Subcommands
+
+| Name                                                | Purpose                                                                       |
+| --------------------------------------------------- | ----------------------------------------------------------------------------- |
+| [<code>decrypt</code>](./server_dbcrypt_decrypt.md) | Decrypt a previously encrypted database.                                      |
+| [<code>delete</code>](./server_dbcrypt_delete.md)   | Delete all encrypted data from the database. THIS IS A DESTRUCTIVE OPERATION. |
+| [<code>rotate</code>](./server_dbcrypt_rotate.md)   | Rotate database encryption keys.                                              |