feat: add helm deployment setup

[bcho]

Sample

helm upgrade \
    -n b4fun-brain \
    --install \
    --set server.secretNameAuthToken=b4fun-brain-auth-token \
    --set server.securityAllowTable='test' \
    --set migrations.enabled=true \
    --set migrations.configMapName=b4fun-brain-migrations \
    --set litestream.enabled=true \
    --set litestream.secretName=b4fun-brain-litestream \
    --set data.enabled=false \
    b4fun-brain ./sqlite-rest