docs: remove wrong documentation on lifecycle of single Pods

[RealAnna]

Summary

Keptn does not track single pods lifecycle but only Workloads (Deployments, Daemonsets,StatefulSets...)
Some places in the docs where not superclear about this so edited them.

Fixed some typos as well.

Checks

• My PR fulfills the Definition of Done of the corresponding issue and not more (or parts if the issue is separated
  into multiple PRs)
• I used descriptive commit messages to help reviewers understand my thought process
• I signed off all my commits according to the Developer Certificate of Origin (DCO)(
  see Contribution Guide)
• My PR title is formatted according to the semantic PR conventions described in
  the Contribution Guide
• My content follows the style guidelines of this project (YAMLLint, markdown-lint)
• I regenerated the auto-generated docs for Helm and the CRD documentation (if applicable)
• I have performed a self-review of my content including grammar and typo errors and also checked the rendered page
  from the Netlify deploy preview
• My changes result in all-green PR checks (first-time contributors need to ask a maintainer to approve their test runs)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

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