Macpass: Remove instant Editable behavior

[mstarke]

Currently the Inspector is instantly editable, this seems risky.

Another approach might be to use a dedicated "edit" button and then enable the editing features. If editing is disabled, all attributes are read only.

I'm not sure which way might be good. But it seems a lot of tools that use display and edit in the same spot have this two mode way. 1Password does it this way, offers an easy "start editing" by double-clicking any entry.
Apple's Contracts uses the same way, by letting entries be viewable and one has to explicitly click "edit" and "done" when one wants to make changes.

[mstarke]

This issue is obsolete since the current implementation of the history support allows for "instant editing"

[mstarke]

This is requires something like #48

[mstarke]

Re-opening since experience has shown that edit mode is better to prevent accidental edits.