Support for individual breach ignores

[SlightlyMadGargoyle]

Hi,

This is my solution to issues/72 and linked issues.

It's basically:

• Provide a right click interface on the BreachedEntriedDialog to allow the user to ignore individual breaches as they apply to each entry, or individual breaches as they apply breached usernames
• Store this informtion in the entry's plugin data
• Extend BreachEntry to be aware of whether a breach should be ignored or not.
• Have the checkers check whether a BreachEntry should be ignored prior to adding it to the final breach list.

Amongst all this I

• Added generic extension methods in StringDictionryExExtension to store arbitary data (JSON serializable) data within the entry's plugin data. This could possibly be pushed upstream to keepass2-developerextensions.
• Added an extension method to PwDatabaseExtensions to make the database as modified (see below)

Note that the 'MarkAsModified' methods doesn't seem to work properly yet. It does make changes in the database and marks the database as modified, but the '' doesn't appear at the top of the keepass window. If you close KeePass without saving, your changed perferences are lossed. If however you open an entry dialogue and press cancel.. the '' appears properly. I haven't got to the bottom of this yet and won't be in a position to investigate further for the next month. I wanted to send this lot to you now in case you are interested.

Possible future enhancements

• Utilise the entry properties to store the users other 'ignore' preference, like 'only check entities that have not changes since the breach', 'ignore any deleted entries', ignore expired entries' and 'expire entries that are found to be breached'
• Instead of ignoring items within the Checker,. have the checkers return all items, allow the user to modify their preferences within the breach dialog and update the dialog appropritely.