docs: miscellaneous documentation fixes and updates

- fix some broken hyperlinks
- add additional hyperlinks to references to external documents
- reformat some paragraphs to keep lines under 80 characters
- unify the enumeration style between different parts of the
  documentation
- fix spelling/grammar mistakes
- extend the copyright notice in README.md to be the same as the
  one in COPYING.BSD

Signed-off-by: Karsten Merker <merker@debian.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>