Support used_for_app instead of used_for_fs

docs/usage/cli.en.md

@@ -398,7 +398,8 @@ Optional parameters:
 | `--raw_placement <rules>`      | Specify raw PG generation rules ([details](../config/pool.en.md#raw_placement)) |
 | `--primary_affinity_tags tags` | Prefer to put primary copies on OSDs with all specified tags               |
 | `--scrub_interval <time>`      | Enable regular scrubbing for this pool. Format: number + unit s/m/h/d/M/y  |
-| `--used_for_fs <name>`         | Mark pool as used for VitastorFS with metadata in image <name>             |
+| `--used_for_app fs:<name>`     | Mark pool as used for VitastorFS with metadata in image `<name>`           |
+| `--used_for_app s3:<name>`     | Mark pool as used for S3 location with name `<name>`                       |
 | `--pg_stripe_size <number>`    | Increase object grouping stripe                                            |
 | `--max_osd_combinations 10000` | Maximum number of random combinations for LP solver input                  |
 | `--wait`                       | Wait for the new pool to come online                                       |

docs/usage/nfs.en.md

@@ -58,7 +58,7 @@ To use VitastorFS:
 2. Create an image for FS metadata, preferably in a faster (SSD or replica-HDD) pool,
    but you can create it in the data pool too if you want (image size doesn't matter):
    `vitastor-cli create -s 10G -p fastpool testfs`
-3. Mark data pool as an FS pool: `vitastor-cli modify-pool --used-for-fs testfs data-pool`
+3. Mark data pool as an FS pool: `vitastor-cli modify-pool --used-for-app fs:testfs data-pool`
 4. Either mount the FS: `vitastor-nfs mount --fs testfs --pool data-pool /mnt/vita`
 5. Or start the NFS server: `vitastor-nfs start --fs testfs --pool data-pool`
 

docs/usage/nfs.ru.md

@@ -60,7 +60,7 @@ JSON-формате :-). Для инспекции содержимого БД
    или по крайней мере на HDD, но без EC), но можно и в том же пуле, что данные
    (размер образа значения не имеет):
    `vitastor-cli create -s 10G -p fastpool testfs`
-3. Пометьте пул данных как ФС-пул: `vitastor-cli modify-pool --used-for-fs testfs data-pool`
+3. Пометьте пул данных как ФС-пул: `vitastor-cli modify-pool --used-for-app fs:testfs data-pool`
 4. Либо примонтируйте ФС: `vitastor-nfs mount --fs testfs --pool data-pool /mnt/vita`
 5. Либо запустите сетевой NFS-сервер: `vitastor-nfs start --fs testfs --pool data-pool`