Popover improvements

[aarranz]

Proposed changes

This PR makes some improvement on how Popovers are managed by WireCloud. Main improvement is management of the popover visibility now that we are allowing sticky popovers, as those popovers are not closed on click events, they were remaining in the user interface when moving between tabs, sections and so on, when closing widgets, .... This PR makes WireCloud aware of the widget visibility and hides/displays the popover when required and removes them on widget unload. This PR also fixes some problems when enabling/disabling fullscreen mode and some problems repainting them.

Types of changes

What types of changes does your code introduce to the project: Put an x in the boxes that apply

• [x] Bugfix (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 not work as expected)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [x] I have read the CONTRIBUTING doc
• [x] I have signed the CLA
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added necessary documentation (if appropriate)
• [ ] Any dependent changes have been merged and published in downstream modules

Further comments

N/A

[coveralls]

Coverage increased (+0.06%) to 88.743% when pulling 43c32d2e8c9a470503cfb390d35a5a3585108a57 on aarranz:feature/no-pointer-events-popover into cdcdddda00281fde3746ed48d303bc24d6ed1760 on Wirecloud:develop.