Add support for xmlsec1 1.3

[timofey-barmin]

Description

Add support for xmlsec1 1.3

The feature or problem addressed by this PR

There are two changes in xmlsec1 1.3 that break compatibility for me:

1. From xmlsec repo:

(API breaking change) Changed the key search to strict mode: only keys referenced by KeyInfo are used. To restore the old "lax" mode, set XMLSEC_KEYINFO_FLAGS_LAX_KEY_SEARCH flag on xmlSecKeyInfoCtx or use '--lax-key-search' option for XMLSec command line utility.

I couldn't make it work without passing --lax-key-search to xmlsec1, 'cause in my case it seems like KeyInfo never contains the private key that is used for signature.
Please let me know if you have a better solution.

2. xmlsec1 changed format of the output for signature verification: "OK" -> "Verification status: OK"

What your changes do and why you chose this solution

I am checking the version of the xmlsec1 utility and if it is > 1.3, I am (a) adding the --lax-key-search param; (b) expect proper output during signature verification.

Checklist

• Checked that no other issues or pull requests exist for the same issue/change
• Added tests covering the new functionality
• Updated documentation OR the change is too minor to be documented
• Updated CHANGELOG.md OR changes are insignificant

[miettal]

This works for me! xmlsec 1.3.

[peppelinux]

@c00kiemon5ter it seems good to me, however we really need a CI running tests in all the PRs and branches