Provide Reference guide for the Kanto File Upload (#56)

* Provide Reference guide for the Kanto File Upload

- provided relevant information about available configurations
- added this information to Kanto documentation
- removed unnecessary configuration property "dumpFiles" from template

Signed-off-by: Trifonova Antonia <[email protected]>

web/site/content/docs/references/file-upload-config.md

@@ -0,0 +1,79 @@
+---
+title: "File upload configuration"
+type: docs
+description: >
+  Customize the files transfer to a backend storage.
+weight: 4
+---
+
+### Properties
+
+To control all aspects of the file upload behavior.
+
+| Property | Type | Default | Description |
+| - | - | - | - |
+| featureId | string | AutoUploadable | Feature unique identifier in the scope of the edge digital twin |
+| type | string | file | Type of the files that are uploaded by this feature |
+| context | string | edge | Context of the files that are uploaded by this feature, unique in the scope of the `type` |
+| files | string | | Glob pattern to select the files for upload |
+| singleUpload | bool | false | Forbid triggering of new uploads when there is an upload in progress |
+| checksum | bool | false | Send MD5 checksum for uploaded files to ensure data integrity |
+| stopTimeout | string | 30s | Time to wait for running uploads to finish as a sequence of decimal numbers, each with optional fraction and a unit suffix, such as: 300ms, 1.5h, 10m30s, etc., time units are: ns, us (or µs), ms, s, m, h |
+| delete | bool | false | Delete successfully uploaded files |
+| **Auto upload** | | | |
+| active | bool | false | Activate periodic uploads |
+| activeFrom | string | | Time from which periodic uploads should be active, in RFC 3339 format, if omitted (and `active` flag is set) current time will be used as start of the periodic uploads |
+| activeTill | string | | Time till which periodic uploads should be active, in RFC 3339 format, if omitted (and `active` flag is set) periodic uploads will be active indefinitely |
+| period | string | 10h | Upload period as a sequence of decimal numbers, each with optional fraction and a unit suffix, such as: 300ms, 1.5h, 10m30s, etc., time units are: ns, us (or µs), ms, s, m, h |
+| **Local connectivity** | | | |
+| broker | string | tcp://localhost:1883 | Address of the MQTT server/broker that the file upload will connect for the local communication, the format is: `scheme://host:port` |
+| username | string | | Username that is a part of the credentials |
+| password | string | | Password that is a part of the credentials |
+| **Logging** | | | |
+| logFile | string | log/file-upload.log | Path to the file where log messages are written |
+| logLevel | string | INFO | All log messages at this or higher level will be logged, the log levels in descending order are: ERROR, WARN, INFO, DEBUG and TRACE |
+| logFileCount | int | 5 | Log file maximum rotations count |
+| logFileMaxAge | int | 28 | Log file rotations maximum age in days, use 0 to not remove old log files |
+| logFileSize | int | 2 | Log file size in MB before it gets rotated |
+
+### Example
+
+The minimal required configuration that sets the file type to log.
+
+```json
+{
+    "type": "log",
+    "files": "/var/tmp/file-upload/*.*",
+    "logFile": "/var/log/file-upload/file-upload.log"
+}
+```
+
+### Template
+
+The configuration can be further adjusted according to the use case.
+The following template illustrates all possible properties with their default values.
+
+```json
+{
+    "featureId": "AutoUploadable",
+    "type": "file",
+    "context": "edge",
+    "files": "",
+    "singleUpload": false,
+    "checksum": false,
+    "stopTimeout": "30s",
+    "delete": false,
+    "active": false,
+    "activeFrom": "",
+    "activeTill": "",
+    "period": "10h",
+    "broker": "tcp://localhost:1883",
+    "username": "",
+    "password": "",
+    "logFile": "log/file-upload.log",
+    "logLevel": "INFO",
+    "logFileCount": 5,
+    "logFileMaxAge": 28,
+    "logFileSize": 2
+}
+```