Riscof

- Added return code of 1 on error

- Fixed signature alignment to begin and end at 16-byte boundaries for all header templates.

- Ported CLI to use click package
- Improved documentation for using plugins.
- Added separate paths for dut and ref artifacts.

- Added support for intermediate run start points 1
- --dbfile is added to generate the test-list and then run tests on the target and reference
- --testfile is added to directly run tests on the target and reference (assumes the testlist has been correctly generated)
- --no-ref-run is added so that tests do not run on reference and quit before signature comparison
- --no-dut-run is added so that tests do not run on DUT and quit before signature comparison
- Added a timestamp comment on the generated database.yaml and testlist.yaml files
- Change FXLEN macro to FLEN 8

- Changed CI script from gitlab to github actions
- Removing hosted cgf files
- Removing hosted riscv-test-suite
- Removing hosted database.yaml
- Updated report to capture the version of the riscv-arch-test suite used during run
- Added new cli - 'arch-test' to automatically clone, update and maintain the riscv-arch-test repo
- Using annotated tags for CI releases
- `suite` and `env` are now required cli args
- updated docs
- added new sections on commands and inputs.
- Revised the installation and riscv-arch-test sections.
- Fixed testlist and dbgen usage and formats
- Cleaned up examples.
- Removed testformat spec.
- Removed section on adding new tests.
- Adding new doc on available PLUGINS for RISCOF.
- Fixed links for new repo transition

- Updated docs with guide on running riscv-arch-tests with RISCOF