feat: Extend "pipeline" command functions

Description

• add ci get functionality to obtain pipeline status in JSON format for further processing

• add ability to use JSON list of variables when running the pipeline (so that output from get can be utilized directly):

  glab ci get --pipeline-id 561079421 --branch 679-certify-operator-image  | jq .variables > my_vars.json
  glab ci run --branch 679-certify-operator-image --variables-from my_vars.json --variables-env FOO:barbuz --variables-file /some/path/to-file

• expand ci run options to load file variables alongside with env_var variables.

allowing user to fully reproduce previously ran pipeline with the same variable values as well as fully control pipeline runtime variables.

Related Issue

Closes #1029 (closed)

How Has This Been Tested?

using build from this branch as a daily driver interacting with pipelines

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation
• Chore (Related to CI or Packaging to platforms)