[feature] allow deletion of one or all history entries

[kaikli]

I like the new feature that the numbers entered are saved to a history and can be used again.

But it should be possible to delete one or all entries from the history.

(optional) Allow the user to disable the history function.

[vinaygopinath]

Thanks @kaikli - I was curious how long it would be after the feature is introduced that this project would see a request to be able to delete it :)

I've created a new issue to disable the history feature altogether - See #56
I'll update this issue to track the work for deleting one or more history entries, or all existing history entries.

[vinaygopinath]

Context

A user may want to delete one or more history entries

Solution

Provide options to delete a specified set of entries or all entries

Acceptance criteria

1. In the history screen, add a new three dots menu and a "Clear all" option
2. When the "Clear all" option is clicked, show a dialog with the following properties

• Title: Delete history confirmation
• Description: Are you sure you want to delete all activity history entries? This action is irreversible.
• Positive button: Delete
• Neutral button: Dismiss

3. In the history screen, when a list item is long-pressed, show a new list item selection view, with the long-pressed entry already selected.
4. When one or more list items are selected, show a "Delete" button in the toolbar.
5. When the "Delete" button is clicked, show a dialog with the following properties

• Title: Delete history confirmation
• Description: Are you sure you want to delete the selected activity history entries? This action is irreversible.
• Positive button: Delete
• Neutral button: Dismiss