Refactor getGlobalConfig usages

[JGAntunes]

As part of #1725 we've added a memoise lib to our global-config module as its being required in multiple places such as telemetry and hooks and we wanted to avoid loading the config file multiple times. Ideally the getGlobalConfig should be called once when initialising our command - https://github.com/netlify/cli/blob/master/src/utils/command.js#L82 - and used from there afterwards. This will also allow us to remove the memoise usage afterwards - https://github.com/netlify/cli/blob/master/src/utils/get-global-config.js#L32