[#70] Support bucket/container caching

Mainly it was added because
we need to know if TZ hashing is disabled or not for container

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

docs/gate-configuration.md

@@ -55,6 +55,7 @@ $ cat http.log
 | `tracing`       | [Tracing configuration](#tracing-section)             |
 | `runtime`       | [Runtime configuration](#runtime-section)             |
 | `frostfs`       | [Frostfs configuration](#frostfs-section)             |
+| `cache`         | [Cache configuration](#cache-section)                 |
 
 
 # General section
@@ -285,3 +286,31 @@ frostfs:
 |---------------------------|----------|---------------|---------------|----------------------------------------------------------|
 | `client_cut`              | `bool`   | yes           | `false`       | This flag enables client side object preparing.          |
 | `buffer_max_size_for_put` | `uint64` | yes           | `1048576`     | Sets max buffer size for read payload in put operations. |
+
+
+### `cache` section
+
+```yaml
+cache:
+  buckets:
+    lifetime: 1m
+    size: 1000
+
+```
+
+| Parameter       | Type                              | Default value                     | Description                                                                            |
+|-----------------|-----------------------------------|-----------------------------------|----------------------------------------------------------------------------------------|
+| `buckets`       | [Cache config](#cache-subsection) | `lifetime: 60s`<br>`size: 1000`   | Cache which contains mapping of bucket name to bucket info.                            |
+
+
+#### `cache` subsection
+
+```yaml
+lifetime: 1m
+size: 1000
+```
+
+| Parameter  | Type       | Default value    | Description                   |
+|------------|------------|------------------|-------------------------------|
+| `lifetime` | `duration` | depends on cache | Lifetime of entries in cache. |
+| `size`     | `int`      | depends on cache | LRU cache size.               |