Refactor tool size handling (#1969)

* Add ConfigHandler::toolSize and setToolSize

* Refactor thickness (now toolSize) in CaptureWidget

Signed-off-by: Haris Gušić <harisgusic.dev@gmail.com>

* Fix update of tool size while object is drawn

Signed-off-by: Haris Gušić <harisgusic.dev@gmail.com>

* Rename thickness to tool size across the board

Tool size is the generic term. Depending on the selected tool,
different specialized names are used. This has always been the case
in the config.

Signed-off-by: Haris Gušić <harisgusic.dev@gmail.com>

* Reorder circle count tool

Signed-off-by: Haris Gušić <harisgusic.dev@gmail.com>

* clang-format

Signed-off-by: Haris Gušić <harisgusic.dev@gmail.com>