Fix systemd service example

[mysubb01]

Summary

• update the systemd ExecStart example so JVM options are passed before the module path/main module
• replace UseParallelOldGC with UseParallelGC and set -Dcontainerized=false for the non-containerized service example
• create ~/bin and ~/var/lib/questdb in the setup snippet so first-time installs have the required paths
• fix a few small wording typos on the page

Verification

• source /Users/wy/.nvm/nvm.sh && nvm exec 22.22.2 npx --yes yarn@1.22.22 install --frozen-lockfile
• source /Users/wy/.nvm/nvm.sh && nvm exec 22.22.2 npx --yes yarn@1.22.22 build
• git diff --check

Fixes questdb/questdb#4265
Related to #224 and questdb/questdb#4258