Update ansible-creator upstream docs to reflect the CLI changes

[shatakshiiii]

ISSUE TYPE

• Doc issue

TASKS

• Update homepage to mention "add" subcommand and remove the references of "create" branch.
• Refactor webview part of the documentation: https://ansible.readthedocs.io/projects/creator/collection_creation/
• CLI usage of add subcommand WRT devfile, devcontainer, ee file, plugins(filter, lookup, action)
• Update optional arguments list: https://ansible.readthedocs.io/projects/creator/installing/#optional-arguments

SUMMARY

Related JIRA: https://issues.redhat.com/browse/AAP-34062