[AP-680] Fastsync tables with composite primary key

[koszti]

Description

CREATE TABLE statements not generated correctly by fastsync if table has composite key. The only reason why fastsync is still working with tables with composite PKs is that Snowflake and Redshift don't enforce primary keys.

Fixing it to generate DDLs with composite PKs correctly.

Checklist

• Description above provides context of the change
• Unit tests coverage for changes (not needed for documentation changes)
• Bumping version in setup.py is an individual PR and not mixed with feature or bugfix PRs
• Commit message/PR title starts with [AP-NNNN] if applicable. AP-NNNN = JIRA ID
• Branch name starts with AP-NNN if applicable. AP-NNN = JIRA ID
• Commits follow "How to write a good git commit message"
• Relevant documentation is updated including usage instructions