gplazma: multimap fix op regression

[paulmillar]

Motivation:

Commit ef2dc1e introduced a regression in the multimap plugin. Where the 'op' principal type is used, logins will fail with dCache logging a stacktrace like:

java.lang.RuntimeException: Failed to create principal: java.lang.NoSuchMethodException: org.dcache.auth.OAuthProviderPrincipal.<init>(java.lang.String)
        at org.dcache.gplazma.plugins.GplazmaMultiMapFile$MappablePrincipal.buildPrincipal(GplazmaMultiMapFile.java:148)
        at org.dcache.gplazma.plugins.GplazmaMultiMapFile$MappablePrincipal.buildMatcher(GplazmaMultiMapFile.java:163)
        at org.dcache.gplazma.plugins.GplazmaMultiMapFile.asMatcher(GplazmaMultiMapFile.java:270)
        at org.dcache.gplazma.plugins.GplazmaMultiMapFile.parseMapFile(GplazmaMultiMapFile.java:248)
        at org.dcache.gplazma.plugins.GplazmaMultiMapFile.mapping(GplazmaMultiMapFile.java:216)
        at org.dcache.gplazma.plugins.GplazmaMultiMapPlugin.map(GplazmaMultiMapPlugin.java:37)
        at org.dcache.gplazma.strategies.DefaultMappingStrategy.lambda$map$0(DefaultMappingStrategy.java:57)
        at org.dcache.gplazma.strategies.PAMStyleStrategy.callPlugins(PAMStyleStrategy.java:91)

This problem is because the above commit replaced the single-string constructor that was being used by the multimap plugin via reflection.

Modification:

Define the following semantics:

When op is used as a principal matcher, the matcher will be selected when the login has an OAuthProviderPrincipal with that value as its (dCache) name; for example, op:FOO will match if the login has an OAuthProviderPrincipal with name FOO. The URL of the issuer (the iss claim value) is not considered. This recreates the previous semantics.

When used as a principal, the op takes two colon-sparated arguments: the (dCache) name for the OP and the issuer URL (the iss claim value). For example, op:FOO:https://my-op.example.org/ creates an OP with name FOO and issuer URL https://my-op.example.org/.

For backwards compatibility, if the second colon and the issuer URL is omitted then a placeholder URL is used and a warning is logged; for example, op:FOO will add a OAuthProviderPrincipal with name FOO and a placeholder issuer URL.

Unit tests are added that verify correct behaviour.

Result:

A regression is fixed in the multimap plugin when op: principal type is used.

Target: master
Request: 10.1
Request: 10.0
Request: 9.2
Requires-notes: yes
Requires-book: no
Closes: #7654
Patch: https://rb.dcache.org/r/14314/
Acked-by: Tigran Mkrtchyan