Update sites with new logos

[szymontrocha]

Update docs with:

• New ESnet logo
• Change perfSONAR logo to 20th anniversay logo (for this year only)
• Year to 2025 in the footer
• Bump up version to 5.1.4

Update main site with:

• Change perfSONAR logo to 20th anniversay logo (for this year only)
• Year to 2025 in the footer