Rudder

Given the implementation of boolean options in Rudder directives (a simple checkbox), any Technique variables that are booleans have an "implicit" default value of "false", which is particularly important in the case of migrations.

See #4293 for details of why most users will just click through directive technique version migrations.

Since this default is generally accepted (and some cases where it's not a good idea do already include an explicit default of "true"), and should be harmless in a majority of cases, we should make this explicit. This will greatly aid in migrations once #7872 is implemented.