docs: Bolt to OpenBolt install

[d1nuc0m]

Short description

Edit Bolt install docs to update for OpenBolt - content from OpenVoxProject/openbolt#173

Closed #398 by accident, can't reopen after force push...

CC @bastelfreak @nmburgan @miharp

Still conflicts with #385 , keeping open if other PR needs info from here, or if the two should be integrated

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document and added a Signed-off-by annotation to each of my commits
• read and accepted the AI Policy document and added Generated-by or Assisted-by annotations to each of my commits created with the help of an AI agent
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)

[d1nuc0m]

Regarding OS matrix - I wouldn't mention EOL OSes, even if packages do exist