feat: add meta data to cli output

[jeeyyy]

Log metadata of test engine, environment and runner to cli

Note: to add tests, hence still a draft

Closes issue:

• https://github.com/dequelabs/attest-issues/issues/6
• https://github.com/dequelabs/axe-cli/issues/93 (duplicate)

Reviewer checks

Required fields, to be filled out by PR reviewer(s)

• [ ] Follows the commit message policy, appropriate for next version
• [ ] Has documentation updated, a DU ticket, or requires no documentation change
• [ ] Includes new tests, or was unnecessary
• [ ] Code is reviewed for security by: << Name here >>

[stephenmathieson]

We should also make sure the metadata is outputted in the JSON mode.

[jeeyyy]

Ensured that this metadata is outputted in JSON mode as well by running axe https://deque.com --stdout & got the below.

[dylanb]

reviewed for security retroactively