Docs: new documentation site (#2723)

This commit adds a VitePress build to the main repository,
aiming to ditch GitHub Wiki. Moving further, we're going to
host our own documentation site eithor on GitHub Pages or
something alike.

docs/premium/rule-providers.md

@@ -0,0 +1,100 @@
+---
+sidebarTitle: "Feature: Rule Providers"
+sidebarOrder: 4
+---
+
+# Rule Providers
+
+Rule Providers are pretty much the same compared to Proxy Providers. It enables users to load rules from external sources and overall cleaner configuration. This feature is currently Premium core only.
+
+To define a Rule Provider, add the `rule-providers` field to the main configuration:
+
+```yaml
+rule-providers:
+  apple:
+    behavior: "domain" # domain, ipcidr or classical (premium core only)
+    type: http
+    url: "url"
+    # format: 'yaml' # or 'text'
+    interval: 3600
+    path: ./apple.yaml
+  microsoft:
+    behavior: "domain"
+    type: file
+    path: /microsoft.yaml
+
+rules:
+  - RULE-SET,apple,REJECT
+  - RULE-SET,microsoft,policy
+```
+
+There are three behavior types available:
+
+## `domain`
+
+yaml:
+
+```yaml
+payload:
+  - '.blogger.com'
+  - '*.*.microsoft.com'
+  - 'books.itunes.apple.com'
+```
+
+text:
+
+```txt
+# comment
+.blogger.com
+*.*.microsoft.com
+books.itunes.apple.com
+```
+
+## `ipcidr`
+
+yaml
+
+```yaml
+payload:
+  - '192.168.1.0/24'
+  - '10.0.0.0.1/32'
+```
+
+text:
+
+```txt
+# comment
+192.168.1.0/24
+10.0.0.0.1/32
+```
+
+## `classical`
+
+yaml:
+
+```yaml
+payload:
+  - DOMAIN-SUFFIX,google.com
+  - DOMAIN-KEYWORD,google
+  - DOMAIN,ad.com
+  - SRC-IP-CIDR,192.168.1.201/32
+  - IP-CIDR,127.0.0.0/8
+  - GEOIP,CN
+  - DST-PORT,80
+  - SRC-PORT,7777
+  # MATCH is not necessary here
+```
+
+text:
+
+```txt
+# comment
+DOMAIN-SUFFIX,google.com
+DOMAIN-KEYWORD,google
+DOMAIN,ad.com
+SRC-IP-CIDR,192.168.1.201/32
+IP-CIDR,127.0.0.0/8
+GEOIP,CN
+DST-PORT,80
+SRC-PORT,7777
+```