[jdk17u-dev] RFR: 8314960: Add Certigna Root CA - 2

[Martin Doerr]

Backport of [JDK-8314960](https://bugs.openjdk.org/browse/JDK-8314960).
Applies cleanly except:

- I had to move the certificate due to [JDK-8257733](https://bugs.openjdk.java.net/browse/JDK-8257733).
- Hunks in VerifyCACerts.java very easy to resolve. I had to compute and insert the new checksum.

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Commit messages:
 - Backport e9ba8d5a0e74c7e61f963b9a295662899d0156dd

Changes: https://git.openjdk.org/jdk17u-dev/pull/1715/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1715&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314960
  Stats: 568 lines in 4 files changed: 338 ins; 227 del; 3 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1715.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1715/head:pull/1715

PR: https://git.openjdk.org/jdk17u-dev/pull/1715