chore: apply suggested changes

fix(sparkline): remove border and padding from tooltip

sequel of telerik/kendo-angular#1247

fix(sparkline): remove border and padding from tooltip

sequel of telerik/kendo-angular#1247

refactor(splitter): improve scope of icon styles

fix(grid): improve drag clue layout

The drag clue size is calculated for content-box, which breaks whenever the Bootstrap framework is included.

fix: update Bootstrap dependency to v4 official

fix: update Bootstrap dependency to v4 official

fix(chart): remove spacing from tooltip

solves issues when the popup padding is set (in bootstrap and material)

see telerik/kendo-angular#1247

fix(inputs): apply font-size variable to simple textbox (#853)

see kendo-angular/#1178

fix(grid): (Angular) resize contents to fit wrapper (#859)