feat: add view CRUD APIs (#4236)

A view is a named query a database stores and plans on every read. It
holds no rows, which is the whole difference from a materialized view.

## API

| Verb | Route |
| --- | --- |
| `create_view(name, query, namespace_path)` | `POST
/v1/view/{id}/create` |
| `describe_view(name, namespace_path)` | `POST /v1/view/{id}/describe`
|
| `drop_view(name, namespace_path)` | `POST /v1/view/{id}/drop` |
| `list_views(namespace_path)` | `GET /v1/namespace/{id}/view/list` |

On `Connection` and the `Database` trait, with the remote client, Python
(sync and async) and Node bindings. Local databases return
`NotSupported`: the server side is Sophon's, where a view is an object
of the database manifest.

`ViewDescription` carries the defining query, the database *and
namespace path* unqualified names in it resolve against, and the schema
the query resolved to. `create_view` returns one, so a caller has the
schema without a second call.

Both defaults travel with the view because it outlives the session that
declared it: the server re-plans the stored query on every read, so a
reader resolving an unqualified name against its own defaults would read
a different table. `default_namespace_path` crosses the wire as
`default_namespace`, a path like `namespace`, absent for the root.

There is no replace: a name already taken is an error, and changing a
view is a drop followed by a create, each authorized against what it
actually touches.

Querying a view stays SQL's job. There are no rows behind a view, so
there is no `open_view` returning a `Table`.

docs/src/js/classes/Connection.md

@@ -319,6 +319,38 @@ Creates a new Table and initialize it with new data.
 
 ***
 
+### createView()
+
+```ts
+abstract createView(
+   name,
+   query,
+   namespacePath?): Promise<ViewDescription>
+```
+
+Create a view: a named query the database plans on every read.
+
+The query is planned once, at creation, so one that cannot be planned is
+rejected now rather than at the first read. A view holds no rows, and its
+readers see its sources as they are at read time.
+
+There is no replace: a name already taken is an error, and changing a
+view is a drop followed by a create.
+
+#### Parameters
+
+* **name**: `string`
+
+* **query**: `string`
+
+* **namespacePath?**: `string`[]
+
+#### Returns
+
+`Promise`&lt;[`ViewDescription`](../interfaces/ViewDescription.md)&gt;
+
+***
+
 ### describeNamespace()
 
 ```ts
@@ -342,6 +374,27 @@ The namespace's properties
 
 ***
 
+### describeView()
+
+```ts
+abstract describeView(name, namespacePath?): Promise<ViewDescription>
+```
+
+What this database records about the view named `name`: its defining
+query and the schema that query resolved to.
+
+#### Parameters
+
+* **name**: `string`
+
+* **namespacePath?**: `string`[]
+
+#### Returns
+
+`Promise`&lt;[`ViewDescription`](../interfaces/ViewDescription.md)&gt;
+
+***
+
 ### display()
 
 ```ts
@@ -498,6 +551,28 @@ on the returned job to know when cleanup has finished.
 
 ***
 
+### dropView()
+
+```ts
+abstract dropView(name, namespacePath?): Promise<void>
+```
+
+Drop the view named `name`.
+
+The tables it reads are untouched: a view holds no rows of its own.
+
+#### Parameters
+
+* **name**: `string`
+
+* **namespacePath?**: `string`[]
+
+#### Returns
+
+`Promise`&lt;`void`&gt;
+
+***
+
 ### isOpen()
 
 ```ts
@@ -636,6 +711,26 @@ A page of table names and an
 
 ***
 
+### listViews()
+
+```ts
+abstract listViews(namespacePath?): Promise<string[]>
+```
+
+The names of the views in one namespace.
+
+Names only; a definition comes from [describeView](Connection.md#describeview).
+
+#### Parameters
+
+* **namespacePath?**: `string`[]
+
+#### Returns
+
+`Promise`&lt;`string`[]&gt;
+
+***
+
 ### openJob()
 
 ```ts