Implement a RTL support for the more complex Vaadin components

Originally by @johannest

Implement a RTL support for for the more complex Vaadin components. Assumed changes/tasks are listed below of each widgets. Separate tickets should be created for each component if/when the implementation is started. NOTE! Task list is incomplete and should be updated.

ComboBox
- css changes
- Changes in VFilterSelect
- tb and popupOpener in different order
- setSelectedItemIcon, icon placement
- getDisplayString(), icon string placement
- popup up-down elements on the left-hand side
- page number (status-element) on the left-hand side
- default RTL tab indices
- RTL tooltips

- testing (manual and TB tests)		

TabSheet
- css changes
- Changes in VTabsheet
- default RTL tabulator indices
- TabCaption RTL caption, closebox, icon
- reversed indices for Tabs
- tab scrollers on the left-hand side
- move scrollbar of the tabPanel on the left-hand side (by css?)
- check clipping from other side if needed (?)
- RTL tooltips
- testing (manual and TB tests)

Table
- server side changes
- default Align.RIGHT
- css changes
- Changes in VScrollTable
- vertical scrollbar on the left-hand-side
- reversed column order in several places
- HeaderCell mirrored
- sortIndicator
- captionContainer
- resizeWidget
- TableHead
- columnSelector on the left hand side
- default ALIGN_RIGHT
- FooterCell mirrored
- default TextAlign.RIGHT
- TableFooter
- default ALIGN_RIGHT
- VScrollTableBody
- ALIGN_LEFT --> ALIGN_RIGHT
- VScrollTableRow
- chidWidgets in reversed order
- TooltipInfos
- buildCaptionHtmlSnippet reversed
- RTL to LTR and back logic
- testing (manual and TB tests)

• DateField

• OptionGroup
• PasswordField
• Calendar
• ListSelect
• TwinColSelect
• Tree
• TreeTable

Imported from https://dev.vaadin.com/ issue #16549

Start by splitting the work into component-specific tickets, using VFilterSelect, VTabsheet, and VScrollTable as the named entry points. Trace their CSS and server-side code; the issue names manual and TB tests but gives no file or test paths, and completion would require covering the listed RTL behavior for each component.