docs: add docs on modules (backport #2269)

.gitignore

@@ -5,7 +5,7 @@ release/
 docs/tla/states/
 *.out
 vendor/
-build/
+/build/
 .vscode
 .idea
 __debug_*

docs/build_deploy.sh

@@ -5,10 +5,5 @@ echo "building docusaurus main docs"
 cp supported_versions.json versions.json
 npm ci && npm run build
 
-# copy "legacy" docs directory into the final build directory
-# the directory is in "docs/legacy" of the source branch (legacy-docs-page)
-# the build environment must be in "./docs" for this to work as expected
-git checkout origin/legacy-docs-page -- legacy
-cp -r ./legacy ./build/
 mv build ~/output
 echo "done building docusaurus main docs"

docs/docs/build/_category_.json

@@ -0,0 +1,4 @@
+{
+  "label": "Build",
+  "position": 3
+}

docs/docs/build/modules/01-overview.md

@@ -0,0 +1,22 @@
+---
+sidebar_position: 1
+---
+
+# Overview
+
+ICS consists of two main modules:
+
+* [x/provider](./02-provider.md)
+  * Provides to consumer chains updated information of opted in validators.
+  * Distributes ICS rewards to opted in validators.
+  * Jails and slashes validators that misbehave on consumer chains.  
+* [x/consumer](./03-consumer.md)
+  * Sends to the consensus engine the validator sets received from the provider chain.
+  * Splits consumer block rewards and sends ICS rewards to the provider chain. 
+  * Notifies the provider chain of downtime infractions. 
+
+Note that `x/types` contains types shared by both modules.
+
+In addition, the following modules are added to ICS to extend its functionality:
+
+* [x/democracy](04-democracy.md)