fix alt text and figure out why images are missing

[rabbah]

Visit https://docs.nimbella.com/deploy-from-github and you'll see this at the end bottom of the page:

There are three references to this the code base, as alt-text for images. https://github.com/nimbella/docs/search?q=Docusaurus+with+Keytar

https://github.com/nimbella/docs/blob/877fecaa36d480b281066a8ed23d055fd37879f8/docs/key-value-storage.md#L36 https://github.com/nimbella/docs/blob/5bdc4b88c42ed39c94807dd7ed25dc466df4613f/docs/project-creating-your-own.md#L21 https://github.com/nimbella/docs/blob/5bdc4b88c42ed39c94807dd7ed25dc466df4613f/docs/deploy-from-github.md#L39

[rabbah]

Fixed by https://github.com/nimbella/docs/commit/28e97404e87801e7c47f1ad98240985bf5737cc2 https://github.com/nimbella/docs/commit/51c94af6e7639b4978ad08bac6c33083eeb8f592 and https://github.com/nimbella/docs/commit/0038e07fd4a96f4c993bedec2b64dd5a4164f3ec.