Show save dialog on hover

[boriskovar-m2ms]

See this example: https://codepen.io/alexd2/pen/PRbjxz/
This change will affect the behavior of the save button where contents of save dialog (for both project and snapshot) will be displayed in this style of the dialog.

Additionally this mechanism will be used for switching between snapshots in project history tree. When you click (or hover?) on the circle representing snapshot there are options:

1. current snapshot is not modified - snapshot will be switched without any other action required by the user
2. current snapshot is modified - dialog will be displayed (same style like in the example) with three buttons: 'Switch', 'Quick Save' and 'Save'

• 'Switch' - will switch to clicked snapshot without saving

• 'Quick Save' - will save snapshot with default values and switch to clicked snapshot

• 'Save' - will show save dialog (same style like in the example) where user is able to change default values and after saving a snapshot will be changed to clicked one.

• part of the issue is creating generalized component that can be attached to any other component with contents of defined by the user of the component and will slide out on hover or click.

[phraenquex]

This hover-and-display function will be useful for many modals, e.g. the [F] button on the RHS, or the tags on the LHS.

[boriskovar-m2ms]

Going to park this ticket for few days because there is a very strange issue with underlying component (Popover). When I provide it with anchor element as an object it says it wants function and when I give it function it says it wants object.

Warning: Failed prop type: Invalid prop `anchorEl` supplied to `ForwardRef(Popover)`, expected one of type [function].

Warning: Failed prop type: Material-UI: The `anchorEl` prop provided to the component is invalid.
It should be an Element instance but it's `[object Object]` instead.

EDIT: This seems to be a very weird manifestation of other problem and anchor element should be object but there is something wrong with the element.