Add code block copy and collapse functionality

[GimleLarpes]

Description

The ability to copy and collapse code blocks have been requested in #1110 and #1592. This PR aims to add this functionality in a similar way to Element web and Discord.

This PR makes it so that:

• Large code blocks (currently more than 14 lines) are collapsed into a scrollable 10-line preview that can be expanded to the full message length
• Adds a copy button that copies the contents of the code block
• Adds a collapse/expand button to code blocks

This prevents large code blocks from clogging up conversations.

Example Images

Collapsed, non-hovered

Expanded, hovered

Fixes #1110, Fixes #1592

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [o] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [o] This change requires a documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings