Add parameter skip_install to gcp-cli/setup

[w1mvy]

Checklist

• [x] All new jobs, commands, executors, parameters have descriptions
• [x] Examples have been added for any significant new features
• [x] README has been updated, if necessary

Motivation, issues

Hi. This orb has always helped me!!

When orbs was upgraded from v2 to v3, it now calls the install command inside gcp-cli/setup as well, which causes failure uninstall step when use an image which gcloud is installed. (We used image based on google/cloud-sdk:alpine, work around it by installing the sudo command, but we don't want to reinstall itself).

It is helpful that gcp-cli/install runs automatically, but it would be more convenient to have the ability to skip.

Description

Add parameter skip_install in gcp-cli/setup command

[andrelegault]

Skipping the installation of the sdk makes the most sense to me given the fact that some installations are done using package managers which won't work with this orb's usage of gcloud components install (docs) to reinstall components. ~A current workaround for this is to leverage https://github.com/CircleCI-Public/gcp-cli-orb/pull/77 and pin a version lower than what's currently installed~ I misunderstood the PR, the uninstall is only skipped if you have a version more recent than the latest version the orb finds. That being said, having the option to explicitly skip the install would be nice.