Feature/expandable row

[LighthouseKeeperYN]

close #2837

Adds expandable row for data table.

Breaking changes: cell slot bindings were changed from cell to { cell, row }. row property is necessary to access expandable row trigger method.

Types of changes

• Bug fix (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)
• Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)

[m0ksem]

Looks cool.

Found few issues:

• No collapse animation (expand animation looks good)
• Missing --expanded classes. It is a normal practice to add some background to an expanded row, people must have classes for it. For example:

[aluarius]

Smthng happens for VaDataTable.new.demo.vue. It worked before, so, something goes wrong.

[m0ksem]

I changed demo a bit, so it looks a bit interesting:

Also, I moved back rowData to slot binds and added it to expandableRow.