docs: Add ASF attribution

[simicd]

Which issue does this PR close?

Closes #185

Rationale for this change

Aligning Apache Software Foundation attribution across projects

What changes are included in this PR?

• Update ASF footer
• Add trademark statement
• Create docs README with instructions on how to run doc builder similar to e.g. arrow-ballista or arrow-datafusion repo

Are there any user-facing changes?

Updated footer on documentation website

Previously

Newly

[simicd]

Thanks a lot for the thorough review @kou, very helpful! I accepted all changes, there are two comments left above