feat(zsh): organize p10k configuration into separate files

[denolfe]

• Moves all personal customizations and custom prompts to zsh/p10k.customizations.zsh
• Regenerates p10k config using the following options:

# nerdfont-v3 + powerline, small icons, rainbow, unicode,
# round separators, blurred heads, round tails, 2 lines, disconnected, no frame,
# compact, many icons, concise, instant_prompt=verbose.