doc/dev-{algo,client,server}.md: converted and split from dev.org

see #3932

pandoc --wrap=preserve --atx-headers -s -r org doc/dev.org -t gfm > doc/dev.md
1 job for doc/split-dev-doc in 6 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test Tools
passed #363305
test_tools

00:00:06