Colorpicker validation handling (#10821)

Colorpicker validation handling (#10821)

* ColorTextField, helper methods, and regex for validating and handling text input

* Refactored structure to avoid creating new component for validation

* Style to adapt to error indicator

* Tests for validating input in ColorPickerPreview component's TextField

* Merge branch 'master' into colorpicker_validation

* Fix path to server class

* Fix test: Submit the new value

* Fix test: ignore Phantom JS

* Fix hsl+hsla validation patterns to accept '%', test value tweaking

* Merge branch 'master' of github.com:vaadin/framework into colorpicker_validation

* Fix: remove warning when color is updated from elsewhere

* Revisions: input validation only once, Logging level WARN

* Revisions: unit tests for color pattern matching

* Revisions: moved parsing to utility class, tests for parsing all accepted input formats

* Fixed import in tests, comments

* Revisions: Logger as constant, ignore utility class in serialization test

* Corner case tests

* Revisions: protected method for parsing error text, fix to test

* Revisions: NPE fix