Port all relevant changes from FW since 8.0

[pleku]

Need to search for the latest change ported from vaadin/framework and then systematically import all relevant changes to Flow. There aren't that many, but still there is some.

No documentation changes should be ported. No Component based changes should be ported.

One thing to look for is Binder and DataProvider related changes (if those have any documentation updates). Binder should not have that much difference between 8 and Flow, but for DataProvider there might be some differences.

[Legioth]

More specifically, #1220 states that the last commit that has been considered for inclusion is 7f1cfd03d5b55f41ea911fcd53ce6fd168517cff. To make it easier to keep track of what to look at in the future, I'd suggest always doing one minor at a time. This means that this effort would end at 7fb7f7d3220ab2eb2b42f52d240fd3a587812bde which was the last commit on master that is also part of version 8.1.

[pleku]

Currently, the latest ported change from V8 to Flow is vaadin/framework@e597d0c

[ZheSun88]

since last comment from Pekka on 13 March, port change details are recorded here #3592

30 May, the following port change will be provided from vaadin/framework@e597d0c...8.4.2

Commit list -> https://docs.google.com/spreadsheets/d/1tRovgBPgjKKO7P3C3pGmhW2gsYd6F7NIqETHJn_dTKM/edit#gid=0

7 commits have been ported to flow, mainly about binder or data-binding. some tests have been moved to the component repository.