QtIFW

Clarify the add/remove components string to make it clearer

Since there is generally confusion as to what will be installed,
removed or updated the string is clarified further to hopefully
make it much more clearer what will happen depending on whether
it is checked or not.

Change-Id: I1077b3dd3e4511e01ca64d0598942d5254e33a54
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Katja Marttila <katja.marttila@qt.io>