no spec content changes, just long list of workflow/infra change:

* update Makefile (src/build dir; html output;)
* update docs-resources to lastest commit
* adoc attributes
  * include global attributes from docs-resources
  * fix others to reflect src/build
* move spec files to src dir
* update github actions to latest
* install pre-commit (config file and github action)
* update README.adoc
  * add MAINTAINERS, CONTRIBUTING, CODE_OF_CONDUCT files

relates to #340

Signed-off-by: Kevin Broch <kbroch@rivosinc.com>