[KJots] Provide explicit "Save" action, use standard actions where possible

Summary:
Use some standard actions for save, next page, previous page, rename.
Add "Save" action to menu and toolbar, otherwise it's not even clear how to save the note.
Don't use QInputDialog when renaming, just trigger inline rename.

Also, perform save procedure on quit (inside KJotsWidget::queryClose).
TODO: this is not yet functional, need to perform a synchronous job and wait for result.

CCBUG: 255998
CCBUG: 296242

Test Plan: All actions are functional

Reviewers: dvratil

Reviewed By: dvratil

Subscribers: kde-pim

Tags: KDE PIM

Differential Revision: https://phabricator.kde.org/D29291