chore: support external cert-manager

[odubajDT]

Changes

• added ca-injection annotations to webhooks and CRDs
• update documentation how to use external cert-manager

Fixes: #1809

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[codecov]

Codecov Report

Merging #1864 (9a1fa89) into main (f25b24d) will decrease coverage by 24.91%.
Report is 3 commits behind head on main.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1864       +/-   ##
===========================================
- Coverage   83.50%   58.59%   -24.91%     
===========================================
  Files         136       35      -101     
  Lines        8292     2408     -5884     
===========================================
- Hits         6924     1411     -5513     
+ Misses       1114      860      -254     
+ Partials      254      137      -117     

see 115 files with indirect coverage changes

Flag	Coverage Δ
certificate-operator	68.55% <ø> (ø)
lifecycle-operator	?
metrics-operator	?

Flags with carried forward coverage won't be shown. Click here to find out more.

[StackScribe]

Lines 17-22 need a little rewrite -- something like the following although I may have screwed up the termology a bit:

KLT also works well with the
cert-manager.io
controller to support other certificate issuers.
If you are already using a different cert-manager,
you can continue to use that cert-manager for other components
and use the KLT cert-manager just for KLT activities
or you can disable the KLT cert-manager
and configure KLT to use the cert-manager.io controller.

[StackScribe]

Need to modify the cert-manager page under Architecture.

First, end the first section with just the mention that you can use an alternate cert-manager and say "See below" or something -- remove the link to the instructions.

Then add a section at the end of this page. Something on the order of:

Using KLT with another cert-manager

KLT can co-exist with cert-manager.io
or can be configured to use cert-manager.io instead of the built-in KLT cert-manager;
see Use Keptn with cert-manager.io
for instructions.

When KLT is initialized on the namespace,
it checks whether the built-in cert-manager has been disabled.

• If it has not been disabled, KLT uses it.
• If the built-in cert-manager has been disabled,
  KLT looks for the cert-manager.io Certificate and Issuer resources
  and configures the Webhook to use that cert-manager instead.
  Note that you can not modify the cert-manger on a running KLT instance.

Question: can they modify, say, the dnsNames fields in the Certificate
or the spec for the Issuer without reinstalling KLT?

[StackScribe]

Nicely done. I made a couple suggestions for you to consider -- just to provide a bit more context here

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
1 Code Smell

No Coverage information
0.1% Duplication

[odubajDT]

Nicely done. I made a couple suggestions for you to consider -- just to provide a bit more context here

Thank you, applied some of them, but as this is still in progress, it will change in the time :)