Adjusted tables to support SUBJ_ID's of 30 chars (FT-743)

OpenClinica has subject names of 30 character max. To support the automatic
upload of data from OpenClinica we have to meet this.
From i2b2 I had to adapt patient_dimension.sourcesystem_cd <study:visit:subject>
Merge pull request #7 from thehyve/extend-SUBJ_ID-size

Adjusted tables to support SUBJ_ID's of 30 chars (FT-743)