the new rule saying that people must have stayed in Denmark or another EU/EEA country for 7 out of the last 12 years, is a specific danish law/rule.
But the new law will be phased in over three years, so in 2019 the requirement is "only" 5 out of the last 12 years.
So you should be able to fulfill the requirement, as you have stayed here since 2013.
When you move to another EU country your earned rights (membership periods in A-kasse and periods of work) must be taken into account in the new EU country according to the EU legislation.
According to the EU legislation you have the right to “take the membership" with you when you move between EU/EEA countries.
However the individual EU countries can have their own special rules about Unemployment Insurance and benefits, as long as they don't discriminate between their own population and EU citizens.
And requirements for being eligible for Unemployment benefits varies a lot between different EU countries. So you must find out what are the requirements of the EU country you are planning to move to.
However, normally there should be no problem with transfering rights within EU.
You can read more in our article about transfering rights (membership and working periods) within EU.