Play UI: Keep controls in place when the page is scrolled horizontally

[alexey-milovidov]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Play UI: Keep controls in place when the page is scrolled horizontally. This makes edits comfortable even if the table is wide and it was scrolled far to the right. The feature proposed by Maksym Tereshchenko from CaspianDB.

Hello! My point that Datagrid's scroll should be independent from SQL query window

A test:

SELECT repeat('Hello, world! ', 100), repeat('Hello, world! ', 100), repeat('Hello, world! ', 100) FROM numbers(1000)

Tested in Firefox and Chromium.