ci: migrate localnet to github actions (#4878)

## Description

This PR moves `localnet` from circleci to github actions.

Would we like to add longer lived nets?

Closes: #XXX

.github/workflows/lint.yaml

@@ -1,4 +1,7 @@
 name: Lint
+# Lint runs golangci-lint over the entire Tendermint repository
+# This workflow is run on every pull request and push to master
+# The `golangci` job will pass without running if no *.{go, mod, sum} files have been modified.
 on:
   pull_request:
   push:

.github/workflows/net.yml

@@ -0,0 +1,26 @@
+name: Net
+# Net creates a 4 node test network with docker-compose
+# This workflow is run on every pull request, if a *{.go, .mod, .sum} file has been modified, and push to master and release/** branches
+on:
+  pull_request:
+    paths:
+      - "**.go"
+      - "**.mod"
+      - "**.sum"
+  push:
+    branches:
+      - master
+      - release/**
+
+jobs:
+  net-short:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: 10 Blocks
+        run: |
+          set -x
+          docker run --rm -v "$PWD":/go/src/github.com/tendermint/tendermint -w /go/src/github.com/tendermint/tendermint golang make build-linux
+          make localnet-start &
+          ./scripts/localnet-blocks-test.sh 40 5 10 localhost
+# Decide if we want to run longer lived testnets

.github/workflows/proto.yml

@@ -1,4 +1,6 @@
-name: Proto check
+name: Protobuf
+# Protobuf runs buf (https://buf.build/) lint and check-breakage
+# This workflow is only run when a .proto file has been modified
 on:
   pull_request:
     paths:

.github/workflows/tests.yml

@@ -1,4 +1,7 @@
 name: Tests
+# Tests runs different tests (test_abci_apps, test_abci_cli, test_apps)
+# This workflow runs on every push to master or release branch and  every pull requests
+# All jobs will pass without running if no *{.go, .mod, .sum} files have been modified
 on:
   pull_request:
   push: