Remove colored boxes for tips, infos, cautions, ...

In our documentation, we currently use colored boxes to highlight tips, information, cautions, dangers, warnings, and examples. While these boxes draw attention, their colors can make the documentation harder to read.

One way to address this is to refactor sections and paragraphs to integrate the content from these boxes directly into the text, using only simple formatting (bold, italic, etc.).

Since this is a significant effort, we should implement it gradually, removing these boxes whenever we update the documentation. Attempting to fix all of them in a single PR would likely take too long.

This is a low-priority task.

Example:

• Nice and simple: https://docs.oasis.io/node/run-your-node/
• Bloated with boxes: https://docs.oasis.io/node/run-your-node/validator-node

Start by comparing the box-heavy validator-node page at docs.oasis.io/node/run-your-node/validator-node with the simpler docs.oasis.io/node/run-your-node/ page. Identify one documentation page to update incrementally, then confirm that its tips, information, cautions, dangers, warnings, and examples are integrated with simple formatting while preserving their meaning.