Migrate Moodle Mobile publishing scripts to Gulp tasks

Right now the Mobile app uses several scripts for common tasks related to publishing.

Those scripts should be migrated to Gulp tasks so they are available among the other tasks already implemented.

Tasks

• Migrate the prepare-release-version.sh script to gulp task
• Migrate the prepare-release-integration.sh script to gulp task
• Improve previous scripts to compile the resulting app via Phonegap Build API
• Migrate the rest of scripts that synchronizes language translations

Requirement for prospective student

We require prospective students to set-up a local development environment of the Mobile app (and run it locally) following this documentation: Setting_up_your_development_environment_for_Moodle_Mobile_2, students must provide a video or detailed screenshots including a detailed explanation of what they did to run the app locally.

Skills required	Javascript
Difficulty level	Medium
Possible mentor	Juan Leyva

:: several scripts: https://github.com/moodlehq/moodlemobile-scripts