plan: web previews for channels (#7022)

* plan: web previews for channels

* types for recipient side to support channel web previews and domain names

* fix

* migrations

* update schema and api types

* update schema

* rename migrations

* core: check member role

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

bots/api/TYPES.md

@@ -146,6 +146,7 @@ This file is generated automatically.
 - [Profile](#profile)
 - [ProxyClientError](#proxyclienterror)
 - [ProxyError](#proxyerror)
+- [PublicGroupAccess](#publicgroupaccess)
 - [PublicGroupData](#publicgroupdata)
 - [PublicGroupProfile](#publicgroupprofile)
 - [RCErrorType](#rcerrortype)
@@ -157,6 +158,7 @@ This file is generated automatically.
 - [RcvFileTransfer](#rcvfiletransfer)
 - [RcvGroupEvent](#rcvgroupevent)
 - [RcvMsgError](#rcvmsgerror)
+- [RelayCapabilities](#relaycapabilities)
 - [RelayProfile](#relayprofile)
 - [RelayStatus](#relaystatus)
 - [ReportReason](#reportreason)
@@ -2499,6 +2501,7 @@ UpdateRequired:
 - userChatRelay: [UserChatRelay](#userchatrelay)
 - relayStatus: [RelayStatus](#relaystatus)
 - relayLink: string?
+- relayCap: [RelayCapabilities](#relaycapabilities)
 
 
 ---
@@ -3068,6 +3071,17 @@ NO_SESSION:
 - type: "NO_SESSION"
 
 
+---
+
+## PublicGroupAccess
+
+**Record type**:
+- groupWebPage: string?
+- groupDomain: string?
+- domainWebPage: bool
+- allowEmbedding: bool
+
+
 ---
 
 ## PublicGroupData
@@ -3084,6 +3098,7 @@ NO_SESSION:
 - groupType: [GroupType](#grouptype)
 - groupLink: string
 - publicGroupId: string
+- publicGroupAccess: [PublicGroupAccess](#publicgroupaccess)?
 
 
 ---
@@ -3341,6 +3356,14 @@ ParseError:
 - parseError: string
 
 
+---
+
+## RelayCapabilities
+
+**Record type**:
+- baseWebUrl: string?
+
+
 ---
 
 ## RelayProfile