support multiple certificates for root-ca-file and server-cert-file

[mcalmer]

What does this PR change?

Support multiple certificates for root-ca-file and server-cert-file.
First split all files files into single certificates. If multiple certificates are found in root-ca-file or server-cert-file,
use all additional as intermediate CAs.

This means especially for server-cert-file: it must contain the server certificate as the 1st certificate. Additional certificates in the same file are added to intermediate CAs.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• No tests: already covered

• DONE

Links

Issue(s): #8983
Port(s): https://github.com/SUSE/spacewalk/pull/24786

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

If you don't need a changelog check, please mark this checkbox:

• No changelog needed

If you uncheck the checkbox after the PR is created, you will need to re-run changelog_test (see below)

Re-run a test

If you need to re-run a test, please mark the related checkbox, it will be unchecked automatically once it has re-run:

• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

Before you merge

Check How to branch and merge properly!

[cbosdo]

LGTM. I wonder if I need to somehow do something similar in https://github.com/uyuni-project/uyuni-tools/blob/main/mgradm/shared/ssl/ssl.go

[cbosdo]

LGTM. I wonder if I need to somehow do something similar in https://github.com/uyuni-project/uyuni-tools/blob/main/mgradm/shared/ssl/ssl.go

Answer: the go code already handles that: nothing to do here.