Fix issues discovered with collection transactions indexing mechanism

[curvesy]

What was the problem?

Resolves #39

The setAttribute.js file in the indexer use the unexpected function updateCollection and relies on event data instead of the
required transaction parametrs.

How was it solved?

• Remove event data from the setAttribute, and transfer command tx processor
• Remove the attributeSet file
• Remove updateCollection function to match the other commands
• Remove blank lines, multiple white spaces and other syntax issues not caught by the linter.

How was it tested?

manually