Swagger reshaping proposal for recommendation 20

[kshychko]

@rgenoulaz, base on the discussion in #6, I'm raising this issue with the following items for a new PR we agreed on so far:

• Change the name of the resource to make it a plural : unitsOfMeasure.
• Update all parameters to camelCase
• Change the name of one parameter that had a slash in the middle, Update description to contain the old name as information.
• Add the descriptions based on the documentation from UN/CEFACT
• Remove Status parameter/property
• Change commonCode parameter type from query to path

Do you think you could apply the change above using a new PR? If no, please just let me know, I'll be happy to do it using the #6
.
For the rest I'll raise separate issues so we could discuss them and implement as agreed.

[rgenoulaz]

OK sure, let me narrow the PR to these elements only for now.

[rgenoulaz]

done in #14