Undeprecate Attribute Filter PolicyRule plugins "basic:AttributeIssuerRegex" and "basic:AttributeIssuerString"

The PolicyRule plugins "basic:AttributeIssuerRegex" and "basic:AttributeIssuerString" have
been deprecated in IdP V3, but they are still available.

We at SWITCH have identified one use case for us, so we'd like to use these PolicyRule plugins.

Please undeprecate them and move them to the "afp" namespace.

Suggestion for the new identifiers in the "afp" namespace (in analogy to "Requester*":

basic:AttributeIssuerString -> Issuer
basic:AttributeIssuerRegex -> IssuerRegex

The following files are affected (possibly further files too):

idp-attribute-filter-spring/src/main//java/net/shibboleth/idp/attribute/filter/spring/policyrule/impl/AttributeIssuerRegexRuleParser.java
idp-attribute-filter-spring/src/main//java/net/shibboleth/idp/attribute/filter/spring/policyrule/impl/AttributeIssuerRuleParser.java
idp-attribute-filter-spring/src/main//java/net/shibboleth/idp/attribute/filter/spring/impl/AttributeFilterNamespaceHandler.java

The following files are involved, but most probably not affected:

idp-attribute-filter-impl/src/main//java/net/shibboleth/idp/attribute/filter/policyrule/filtercontext/impl/AttributeIssuerPolicyRule.java
idp-attribute-filter-impl/src/main//java/net/shibboleth/idp/attribute/filter/policyrule/filtercontext/impl/AttributeIssuerRegexpPolicyRule.java
idp-attribute-filter-spring/src/main//java/net/shibboleth/idp/attribute/filter/spring/basic/impl/AttributeFilterBasicNamespaceHandler.java

References:
http://marc.info/?l=shibboleth-users&m=149685343428139&w=2