Backend: Make it possible to set a raw variable in our syntax

Release notes

Previously it was impossible to use the $ character inside a variable since $ sign represents a variable expansion (a reference to another variable), in this release, we are introducing the variable: expand: keyword which will allow you to mark a variable as raw, a raw variable is will not be expanded and can contain any special character which will get passed to the GitLab runner as is.

Problem

It's impossible to use $ in variables, a workaround is to use double $ however it seems that it doesn't work with some bash script

solution

Since we do support raw variables let's add a way for our users to define them in our syntax

Proposal

we should add type: raw to our syntax

variables: 
  RAW_VAR:
    value: $myvar
    expand: false #default is true

Implementation Table

Group	Issues	Issue Link	Notes
backend	Backend: Make it possible to set variables as non-expanded in CI/CD Settings > Variables	#361934 (closed)	MVC
backend	Backend: Backend: Make it possible to set a raw variable in our syntax	👈 You are here	MVC
frontend	Frontend: Make it possible to set variables as non-expanded in CI/CD Settings > Variables	#217309 (closed)	MVC
backend	Backend: Allow special characters to be used for raw variable types	#352657 (closed)	MVC
backend	Backend: Make it possible to set variables as non-expanded in Project->pipelines/new	#362539	TBD at a later date
backend	Backend: Make it possible to set variables as non-expanded in Manual Job->Play	#362548	TBD at a later date
backend	Backend: Make it possible to set variables as non-expanded in Project->pipeline_schedules/new	#362549	TBD at a later date