Determine if there's a workable approach for generalized support of the '--default-capabilities' option

[sbabcoc]

'appium' provides the ability to specify default capabilities that get merged into driver session requests. A good rationale for integrating this option as a Selenium Foundation local Grid feature is presented here. The challenge is that default capabilities apply to all session requests; however, each driver plug-in can support multiple "personalities", which can be augmented at runtime through driver-keyed modifications in the configuration.

How do we determine which "defaults" to specify if the aggregation of driver "personalities" and configured modifications yields multiple choices?

Note that the use of the --default-capabilities option may be unnecessary, due to the ability to specify personality-keyed session request modifications in the configuration. Another approach is to simply use the generic APPIUM_CLI_ARGS setting.