* docs: rework sandbox guide

* update doc name

* add missing comment to code sample

* Update docs/tutorial/sandbox.md

Co-authored-by: Samuel Attard <samuel.r.attard@gmail.com>

* Update docs/tutorial/sandbox.md

Co-authored-by: Samuel Attard <samuel.r.attard@gmail.com>

* Update docs/tutorial/sandbox.md

Co-authored-by: Biru Mohanathas <birunthan@mohanathas.com>

* load https in the examples

* change `process` docs to Electron's

* remove bit on chrome://sandbox

 page

* Update docs/tutorial/sandbox.md

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* Update docs/tutorial/sandbox.md

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* clarify sandbox default posture

* clarify tasks sandboxed renderers need ipc for

* clarify polyfilled preload environment

* emphasize that --no-sandbox is bad

* clarify preload polyfill `require`

* format markdown references properly

Co-authored-by: Samuel Attard <samuel.r.attard@gmail.com>
Co-authored-by: Biru Mohanathas <birunthan@mohanathas.com>
Co-authored-by: Jeremy Rose <nornagon@nornagon.net>