Add contributing docs; steps to fork, clone, add, commit/sign, push to Fermyon Cloud Docs.

[tpmccallum]

This is a quick one-pager which will be useful of developers want to contribute to the Cloud Docs in the future. If nothing else it will be handy to have for our internal team (or when onboarding etc.)

Signed-off-by: tpmccallum tim.mccallum@fermyon.com

[karthik2804]

The content looks good to me but as mentioned below, we should possibly standardize how we present shell commands. I just marked one instance of the shell commands for reference.

[mikkelhegn]

LGTM (Once the shell commands are fixed). I'd like to also get to the requirements for the content of a doc. article. E.g., how shell commands are presented, having a ToC at the top of the article, etc. @tpmccallum Do you think this should go into this doc as well?

[tpmccallum]

Hi @mikkelhegn
I have added a ToC to the top of the document which also links to each section heading.
This can be merged if you are happy with the latest changes.

[tpmccallum]

Actually have changed the way ToC is created; now using automated tool in VSCode. Thanks @mikkelhegn for suggesting "Markdown All In One" extension. Works well.

[karthik2804]

LGTM!
Also we should probably do a new commit to add all the required annotations for the codeblocks across the repository (For removing copy button and formatted copy for the shell code blocks)