fix: update grid layout to be usable by theme-bootstrap

[joneff]

While vast, this refactoring is needed for Bootstrap theme to function properly.

[joneff]

Few screens to show the visual differences in theme-bootstrap and the lack of in theme-default

theme-default
before:

after:

theme-bootstrap
before:

after:

Don't mind the pager links in bootstrap theme. That's something entirely different

[inikolova]

Things, which should be fixed:

• Grid headers, toolbar, filter row heights - should be 46px, currently are the same as the grid cells (36px);
• Grid with aggregates and frozen columns - the whole layout is broken. Also, the layout in the Grid / Export to Excel demo;
• Grid grouping header must have the same height in both cases - grouping applied and without grouping;
• Missing top border on k-group-cell;
• Grid headers don't show ellipsis when text overflows;
• Double border on the last row - grid with frozen columns and aggregates;
• Wrong padding on grid filter / column menu popups;
• Wrong border colors of grid headers in IE11;

[inikolova]

Please see my comment

[joneff]

Grid header, toolbar etc height fixed by f862287

[joneff]

@inikolova I think I fixed all the points.

On a side note, since flex does not support text-overflow: ellipsis I switched to using display: block for same of the cases.

[gyoshev]

@joneff please rebase and resolve the conflicts. Also, the commit messages won't push a new version -- consider squashing to a feat: or fix: commit.

[inikolova]

After additional testing I observed the following:

• k-grouping-header is missing display: block definition;
• Currently k-group-indicator is 40px high while it should be the same as a regular button (30px); -> FIXED
• Grid k-grouping-dropclue is currently a vertical line, while it should have before / after elements; -> FIXED
• Wrong .k-drag-clue height -> FIXED

[gyoshev]

@inikolova added the display:block. It is specific to the angular rendering, as we don't use block elements.