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_delete.md

@@ -0,0 +1,34 @@
+<!-- DO NOT EDIT | GENERATED CONTENT -->
+
+# server dbcrypt delete
+
+Delete all encrypted data from the database. THIS IS A DESTRUCTIVE OPERATION.
+
+Aliases:
+
+- rm
+
+## Usage
+
+```console
+coder server dbcrypt delete [flags]
+```
+
+## Options
+
+### --postgres-url
+
+|             |                                                            |
+| ----------- | ---------------------------------------------------------- |
+| Type        | <code>string</code>                                        |
+| Environment | <code>$CODER_EXTERNAL_TOKEN_ENCRYPTION_POSTGRES_URL</code> |
+
+The connection URL for the Postgres database.
+
+### -y, --yes
+
+|      |                   |
+| ---- | ----------------- |
+| Type | <code>bool</code> |
+
+Bypass prompts.