feat: add Zoom and Drag & Drop features

[rtalexk]

First of all, thanks for your work.

This PR makes the following changes:

• Add Zoom and Drag & Drop functionality using Panzoom

When there's a large model, it was sort of difficult to navigate.

• Make the app 'full-screen-like'

Only the sidebar with the Actions, Options and Models is scrollable, the model preview is navigated using the drag & drop feature.

• Sidebar models overflow

Instead of horizontal-scrolling in the sidebar, the text is truncated with elipsis, and it has a tooltip to show the whole content.

• Diagram & Code Tabs repositioned

I did some CSS changes to make the diagram take the whole available space, with this change I made the buttons absolute positioned, but in the Code tab, it was op top of the text, to prevent this, I moved them to the right, also, I added some opacity, which is set to 100 on hover.

And finally, here's a recording of the final result:

https://github.com/koedame/rails-mermaid_erd/assets/16341644/cce37318-ffa0-4c9b-ab31-7507413886c9

[unchidev]

@rtalexk

I'm really happy that you've implemented the feature I wanted! Please wait for my review 🙏🏿 Thank you!

[unchidev]

@rtalexk Considering that text selection and other features would be compromised, I decided to implement it myself. Thank you for providing the idea.

• https://github.com/koedame/rails-mermaid_erd/pull/95

[rtalexk]

@rtalexk Considering that text selection and other features would be compromised, I decided to implement it myself. Thank you for providing the idea.

• Add zoom and move #95

Cool. The goal was to have the D&D feature, that's fine with me. I'll close this PR since this is no longer valid.