Move created_at to member, and make it optional #783

	name: Test
	on:
	push:
	branches:
	- main
	pull_request:
	jobs:
	js:
	name: Test (JS)
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- uses: actions/setup-node@v2
	- run: npm ci
	- run: npm test
	kotlin:
	name: Test (Kotlin)
	runs-on: ubuntu-latest
	steps:
	- name: Checkout project sources
	uses: actions/checkout@v3
	- name: Setup Gradle
	uses: gradle/gradle-build-action@v2
	- name: Validate Gradle Wrapper
	uses: gradle/wrapper-validation-action@v1
	- name: Generate protobufs
	run: dev/kotlin/generate
	- name: Run build with Gradle Wrapper
	run: ./gradlew build
	- name: Gradle Run Tests
	run: ./gradlew kotlin:test

Provide feedback