FR: Add option to show filters inline in the table

My users requested that it would be great to have filters inlined in table so they are easier to find.

I'm thinking that it could be done as in Excel, with an icon next to header name opening a popup:

or as another row just below header (either a real HTML row, or just visually below) with a full filter input as it is now shown in filter popups.

I'm wondering what do you think about it? I could commit some time to work on a PR. I believe this should be optional, to be set by table option `filterListInline: bool` or similar.