rename "Implementing" section to "User guides"

[StackScribe]

"Implementing Keptn applications" (https://main.lifecycle.keptn.sh/docs/implementing/ ) is a lousy title. I propose we rename this section to just "User guides", which is boring but I think will make the information more accessible.

For discussion, how do we arrange the contents?

• Option 1: Leave the contents pretty much as they are, but perhaps move a couple sections around to be in a more logical order
  • Less work to implement
  • Leaves all the titles viewable when you open "User Guides" in the left margin
• Option 2: Create subsections for Metrics, Observability, and Release Lifecycle Maintenance and arrange the existing pages within those subsections. "Integrate" would stay at the top level -- not part of the other sections -- and we might end up with a few more "generic pages"
  • Keeps the left frame list shorter
  • Supports the increased modularity that is coming for Keptn
  • Also requires the user to know, for example, that "Dora metrics" are part of "Observability" rather than "Metrics"

[agardnerIT]

I think start with option 1

[mowies]

i also vote for option 1

[RealAnna]

yes 1 is perfect

[StackScribe]

This is done. The "Implementing Keptn Applications" section is now called "User Guides" but has essentially the same structure as before.