Upgrade Decidim to version 0.14.3

[xredo]

The current installed version is 0.8.3. The process might need to be done in several steps as 0.14 includes some changes that break previous migrations.

Tasks:

• Upgrade Ruby version
• Upgrade Decidim dependencies
• Apply changes mentioned in the upgrade notes
• Check if there is a better supported solution for the decidim-age_action_authorization.
• Check decidim-census behaviour
• Check decidim-diba_census_api behaviour
• Check decidim-ldap behaviour. Some layouts are being overriden

Upgrade Notes

• https://github.com/decidim/decidim/blob/0.9-stable/CHANGELOG.md#v090-2018-2-5
• https://github.com/decidim/decidim/blob/0.11-stable/CHANGELOG.md#0111
• https://github.com/decidim/decidim/blob/0.12-stable/CHANGELOG.md#0120
• https://github.com/decidim/decidim/blob/0.13-stable/CHANGELOG.md#0130
• https://github.com/decidim/decidim/blob/0.14-stable/CHANGELOG.md#0141