docs: Add code style guide (#518)

* Add code style guide

* Add mention of well-known acronyms

* Add naming convention for optional variables

* Apply doc style guide

* Add resource quantity rules

* Clarify identifier names, add more examples

* Add admonition, change world to universe

* Add why we avoid unabbreviated identifier names

* Adjust newline rule

* Add struct and enum naming rule

* Move some rules

* Add missing admonitions, group rules

* Adjust error message rule for more clarity

* Clarify string formatting rules

* Clarify resource rules

* Explain some points why we use snafu

* Inline K8s link

* Adjust CPU resource rule

* Reorder memory resource rule

* Mention that function names can contain indicators to indicate optional values

* Add explanation to named vs unnamed fmt string identifiers

* Add note about long format strings

* Add one more valid example for named format string identifier

* Update UI

* Add UI fix

* Add quote, add example for single-letter identifier

* Add enum / struct item separation notes

* Add a few rules of thumb for error messages

Author: Techassi

modules/contributor/nav.adoc

@@ -3,7 +3,8 @@
 ** xref:steps.adoc[]
 ** xref:testing_on_kubernetes.adoc[]
 ** xref:development_dashboard.adoc[]
-** xref:style_guide.adoc[]
+** xref:code-style-guide.adoc[]
+** xref:docs-style-guide.adoc[]
 ** Implementation guidelines
 *** xref:logging.adoc[]
 *** xref:service_discovery.adoc[]