Service Dialog: Apply gettext on initial values

[mzazrivec]

The fix consists of:

• fix in dialog editor component (for cases when the dialog is being edited)
• fix in dialog use component (for cases when the dialog is being run)
• fix in dialog sample (for cases when the dialog is rendered as a preview in the right cell of explorer screen for)

Before:

After:

https://bugzilla.redhat.com/show_bug.cgi?id=1592573

[miq-bot]

Checked commit mzazrivec@783d967 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. 🍪

[skateman]

@miq-bot assign @martinpovolny