Update scripts to provide Developer Sandbox automatically

[smarek]

• Added Sandbox env variable export and setting the correct permissions in update_wrapper.sh
• GIT Ignoring common directories (latest, user-data-dir)
• Resolving correctly BASEDIR when the run.sh is symlinked into another directory
• Added optional lines to uncomment, to remove API keys missing warning and form of command to run chromium on standard user profile

[ghost]

This doc https://chromium.googlesource.com/chromium/src/+/master/docs/linux_suid_sandbox.md
seems to say chrome_sandbox was removed(almost?), yet I still see it present on 451586/chrome-linux/

IMPORTANT NOTE: The Linux SUID sandbox is almost but not completely removed. See https://bugs.chromium.org/p/chromium/issues/detail?id=598454 This page is mostly out-of-date.
The SUID helper binary is called chrome_sandbox

[Taeclimax]

Good

[Nardol]

Hello,

We wish to revive this project, so we implemented your suggestion here: https://github.com/chromium-unofficial-latest-linux/chromium-latest-linux
The method for sandbox is different, chown and chmod are directly put in update.sh.
The .gitignore and getting directory even with a symlink has also taken into account, thanks.

As for API key, it is planned to let user the choice to set an API key or no, and eventually set if user wants to launch Chromium on user profile or not.
Do not esitate to let us know if you have some suggestions or make pull request.