[core] Add debug endpoints

[ricoberger]

The api server exposed some "/api/debug" endpoints now. These endpoints
can be used to get the "http/pprof" information and to dump an http
request. The debug endpoints can be enabled via the "--api.debug" flag.
By default these endpoints are disabled.

We also fixed some typos in the documentation for the Azure and Helm
plugin. In the Azure we had a wrong link for the permissions
documentation and in the Helm plugin the configuration section was
missing.

Besides the changes from above, we also enabled the secure and http only
flag for the cookie, which is created by the auth middleware when
authentication is enabled.

• I added a CHANGELOG entry for this change.
• I adjusted the corresponding documentation for this change.
• I adjusted the values.yaml file and the documentation for all values.

[codecov-commenter]

Codecov Report

Merging #285 (4eb998d) into main (148ec9d) will increase coverage by 0.35%.
The diff coverage is 84.10%.

@@            Coverage Diff             @@
##             main     #285      +/-   ##
==========================================
+ Coverage   44.45%   44.81%   +0.35%     
==========================================
  Files          95       96       +1     
  Lines        7968     8058      +90     
==========================================
+ Hits         3542     3611      +69     
- Misses       4394     4415      +21     
  Partials       32       32              

Impacted Files	Coverage Δ
pkg/api/middleware/auth/context/context.go	100.00% <ø> (ø)
plugins/applications/pkg/topology/topology.go	100.00% <ø> (ø)
plugins/flux/pkg/sync/sync.go	0.00% <0.00%> (ø)
pkg/api/api.go	5.06% <4.54%> (-0.20%)	⬇️
pkg/api/clusters/cluster/cluster.go	29.79% <95.23%> (ø)
pkg/api/clusters/cluster/defaults.go	100.00% <100.00%> (ø)
pkg/api/middleware/auth/auth.go	96.68% <100.00%> (+0.09%)	⬆️
plugins/applications/applications.go	100.00% <100.00%> (ø)
plugins/applications/pkg/tags/tags.go	100.00% <100.00%> (ø)
plugins/applications/pkg/teams/teams.go	100.00% <100.00%> (ø)
... and 6 more

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