GC-45: Update copyright information:

- Changes to code base were previously done in 2020 as well (based on
git history).

GC-23: Updated documentation related to move of --update-dns-option from server to renew command:

- Updated the server command usage instructions to include reference
to --update-dns-option in the renew command.
- Added relevant documentation on use of the --update-dns-names option
to the usage instructions for renew command.
- Update the CLI examples.

GC-22: Updated CLI and regular documentation for the new CSR options:

- Updated quick usage instructions to give an example of issuing a
server certificate using CSR.
- Updated documentation for server, client, and renew commands.
- Updated CLI examples to include some usage of the --csr option.
- Updated CLI CSR documentation to emphasize that only the public key
is taken from the CSR.

GC-20: Added documentation for status command and fixed output when server/client certificates have been issued:

- Updated quickstart instructions.
- Added more detailed usage instructions describing what information
gets shown.
- Fixed issue with status command reporting no server/client
certificates have been issued even if this is not the case.

GC-18: Added option for generating a new private key during certificate renewal:

- Implemented functional test for the new scenario.
- Fixed incorrect check for client certificate validity in existing
functional test for client certificate renewal.
- Updated documentation to include information about generating a new
private key during certificate renewal.
- Added option of generating a new private key to the renewal command.
- Updated existing code to use new signature for renewal command and
function.
- Added inline function documentation for the renew command code.
- Implemented relevant unti tests that cover new option.

GC-18: Added documentation for the renew command:

- Updated quick usage instructions.
- Added section covering certificate renewal.
- Updated inline CLI help examples.

GC-19: Added documentation for the --update-dns-names server option:

- Updated CLI help examples.
- Added documentation for the server command describing the
--update-dns-names option
- Fixed invalid documentation for server and client commands that
states the existing artifacts will be overwritten.

GC-16: Added user documentation for the client command:

- Updated the features entry in README file, adding some missing
information about other features implemented as well.
- Added quick usage instruction for issuing a client certificate.
- Added the client certificate artifacts directory to listing of
directories used.
- Added expanded usage instructions for the client command.
- Fixed some invalid invocation example for the server command.

GC-15: Added user documentation for the server command:

- Updated quickstart section to include samples for issuing server
certificates.
- Updated the initialisation section to mention creation of directory
used for storing server private keys and certificates.
- Added new section covering command for issuing server certificates.

GC-3: Added usage instructions to documentation for init command:

- Added beginnings of a quickstart section.
- Added more detailed description on how initialisation behaves, what
it generates and how, and what options can be provided.