lifecycle-toolkit [WIP] Define documentation style issues

Description

We lack standards for some key style issues in the documentation. While these issues are less critical than good content and structure of the docs, consistency gives the docs a more professional look. General proposal is to accept the recommendations in the Google developer documentation style guide, which is comprehensive and reasonable.

Issues

Capitalization for titles. Recommend using sentence case. (See Google Capitalization in titles and headings
American vs. British spelling. We currently have a mix and the Spell checker accepts both. Recommend requiring American spelling. (See Google Spelling and [Wikipedia: Manual of Style/Spelling) )
Sentence structure when telling the reader to do something. Recommend defining what to do before the instructions. (See Google Sentence structure
Use of "please" in instructions. Recommend not using "please". (See Google Politeness and use of please)
Should we recommend timeless documentation that avoids words and phrases that anchor the docs in time? Recommend yes. See Google Timeless documentation
Kubernetes terms
- https://main.lifecycle.keptn.sh/contribute/docs/word-list/#kubernetes-terminology
- Secret or secret
Do we agree to use the Google developer documentation style guide in general? The Contributing Guide currently has this recommendation but we should officially agree to it as a community.
New doc tools cannot handle hyphens in headers. This means we cannot use strings like "pre- or post-deployment" or "pre-defined" in headers. This does not preclude using the hyphenated terms in text but recommend favoring consistency so need to use "pre/post deployment" and "predefined"