addded configurable oai2.xsl style sheet support to proai and oaiprovider

this time the complete code is for xslt-support is pushed. For xslt-support the oaiprovider  needs to use the pushed proai version. If using the release version (1.1.3) of proai, the  proai.stylesheetLocation Property in proai.properties has to be commented. Therefore I changed the version number of proai in my commit to 1.1.3-1, which is not correct I presume? (I'm rather a newbie in commiting code).

I didn't found a Jira ticket associated with my commit wirth in the DuraSpace Jira