Add shellcheck

[apolopena]

Problem this feature will solve

Since this project is almost entirely shell scripts it would be nice to have the option to lint them without any additional setup.

Background

shellcheck is a good bash linter

Proposed Solution

Install shellcheck latest version for all users.

Constraints and Assumptions

Many users wont use this but it is so tiny lets add so that we can use Gitpod to develop this project

Alternatives or Workarounds

Develop this project on the local machine without Gitpod
Or
Just use the command line shellcheck

Additional context

shellcheck cannot be added conditionally to the IDE since it needs to be installed via docker and as an extension in .gitpod.yml

[apolopena]

shellcheck in the IDE cannot ignore files with no extension so the shellcheck IDE extension will not be used.
I devised a command that will inclusively shellcheck just the starter scripts. This has been added as an alias.
alias lint-starter-scripts='find "$GITPOD_REPO_ROOT/.gp" -type d \( -name node_modules \) -prune -false -o -name "*.sh" -exec shellcheck -x -P "$GITPOD_REPO_ROOT/.gp" {} \;'