[Kotlin] Parse @JsonProperty annotation values with spaces

Issue:

When generating a client in Kotlin (from a Kotlin project), @JsonProperty annotation values which have spaces in them are converted to variable names with spaces.
Example:
In project:
@JsonProperty("email address")
val email: String

Result in client:
val email address: String

This of course causes a build failure and thus the only solution at the moment is to not use values with spaces.

Possible solutions:

1. Kotlin does allow for variable and method name declarations with spaces.
   For example, val `email address`: String
2. The space could be replaced with an underscore
3. The name could be parsed to form a word in camelCase (starting with a lower case letter).

No files or tests are named. Start by locating the Kotlin client generator and the handling of JsonProperty values, then reproduce the example with the value "email address". Done means the generated client uses a valid Kotlin declaration and includes a regression test for spaced annotation values.