Layout refactor

[nicosampler]

Closes #1590 by replacing css-grid layout with flexfox.

The current css-grid layout was having some problems, we decided to migrate it to flexbox. Now It adapts better to the structure of the new layout.

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[github-actions]

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Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

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[ghost]

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[ghost]

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[alongoni]

I see two things a bit off.
1- New Transaction Button (Text in two lines)
2- Sidebar scroll at bottom.

I'll try to fix it.

[ghost]

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[ghost]

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[ghost]

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[ghost]

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[alongoni]

https://www.loom.com/share/181f8c6f0c1b46feba3a2f7f5acc34eb
I think it will not affect the scroll.

[ghost]

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[ghost]

Travis automatic deployment:
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