"Select extension" wizard page has layout flaws

[adietish]

Steps:

1. EXEC: launch IDEA, hit "New Project", select "Quarkus" wizard, provide project settings and get to the extensions page

Result: extensions settings page ohas neither left nor right borders

2. ASSERT: the title for the column "Selected extension" is left aligned
3. EXEC: select extension

Result: Now that an extension is selected, the column title "Selected extensions" is right aligned