Add GraphQL ESLint plugin to the codebase

.eslintignore

.eslintrc.yml

.../access_tokens/graphql/queries/get_projects.query.graphql

...vascripts/analytics/shared/graphql/projects.query.graphql

...scripts/boards/graphql/board_list_create.mutation.graphql

...sets/javascripts/boards/graphql/board_lists.query.graphql

...s/javascripts/boards/graphql/group_projects.query.graphql

...vascripts/boards/graphql/issue_move_list.mutation.graphql

...ets/javascripts/boards/graphql/lists_issues.query.graphql

...vascripts/boards/graphql/project_milestones.query.graphql

...ments/graphql/mutations/cancel_auto_stop.mutation.graphql

...nts/graphql/mutations/delete_environment.mutation.graphql

...s/graphql/mutations/rollback_environment.mutation.graphql

...ments/graphql/mutations/stop_environment.mutation.graphql

.../graphql/mutations/update_canary_ingress.mutation.graphql

...s/graphql_shared/queries/group_users_search.query.graphql

...scripts/graphql_shared/queries/users_search.query.graphql

...issues_list/queries/get_issues_list_details.query.graphql

...nnect/branches/graphql/queries/get_projects.query.graphql

...jira_import/queries/get_jira_import_details.query.graphql