UI: Slack source connector (#665)

Author: Paul-Cornell

docs.json

@@ -58,6 +58,7 @@
                   "ui/sources/s3",
                   "ui/sources/salesforce",
                   "ui/sources/sharepoint",
+                  "ui/sources/slack",
                   "ui/sources/snowflake",
                   "ui/sources/zendesk"
                 ]

snippets/general-shared-text/slack-platform.mdx

@@ -0,0 +1,7 @@
+Fill in the following fields:
+
+- **Name** (_required_): A unique name for this connector.
+- **Channels** (_required_): A comma-separated list of the target Slack channel IDs from which to read messages.
+- **Start Date**: The date and time, in ISO 8601 format (such as `YYYY-MM-DDTHH:MM:SSZ`), from which to begin reading messages. Messages created before this timestamp are ignored. By default, all messages are read unless an end date is specified.
+- **End Date**: The date and time, in ISO 8601 format (such as `YYYY-MM-DDTHH:MM:SSZ`), at which to stop reading messages. Messages created after this timestamp are ignored. By default, all messages are read unless a start date is specified.
+- **Bot Token** (_required_): The access token for the Slack app that has permission to read messages from the target Slack channels.

ui/connectors.mdx

@@ -29,6 +29,7 @@ Unstructured supports connecting to the following source and destination types.
 - [S3](/ui/sources/s3)
 - [Salesforce](/ui/sources/salesforce)
 - [SharePoint](/ui/sources/sharepoint)
+- [Slack](/ui/sources/slack)
 - [Snowflake](/ui/sources/snowflake)
 - [Zendesk](/ui/sources/zendesk)
 

ui/sources/overview.mdx

@@ -40,6 +40,7 @@ To create a source connector:
    - [S3](/ui/sources/s3)
    - [Salesforce](/ui/sources/salesforce)
    - [SharePoint](/ui/sources/sharepoint)
+   - [Slack](/ui/sources/slack)
    - [Snowflake](/ui/sources/snowflake)
    - [Zendesk](/ui/sources/zendesk)
 

ui/sources/slack.mdx

@@ -0,0 +1,30 @@
+---
+title: Slack
+---
+
+import FirstTimeUISourceConnector from '/snippets/general-shared-text/first-time-ui-source-connector.mdx';
+
+<FirstTimeUISourceConnector />
+
+Ingest your files into Unstructured from Slack.
+
+The requirements are as follows. 
+
+import SlackPrerequisites from '/snippets/general-shared-text/slack.mdx';
+
+<SlackPrerequisites />
+
+To create the source connector:
+
+1. On the sidebar, click **Connectors**.
+2. Click **Sources**.
+3. Click **New** or **Create Connector**.
+4. Give the connector some unique **Name**.
+5. In the **Provider** area, click **Slack**.
+6. Click **Continue**. 
+7. Follow the on-screen instructions to fill in the fields as described later on this page.
+8. Click **Save and Test**.
+
+import SlackFields from '/snippets/general-shared-text/slack-platform.mdx';
+
+<SlackFields />