[Feature][config:export] Allow to skip config export of modules.

[joshirohit100]

We have command to export all configuration and export single one but there are certain modules which we require on local but not on other environments. So there should be a way not to export (skip) config of those module in export.

config:export --skip=mymoduleA, mymoduleB

or we can go by individual files. Thoughts ?

[cburschka-pwc]

Note that there is no clear mapping of config to modules - though you might filter configuration objects by name, or by their dependencies.

When filtering by name, it might be more convenient to maintain a .gitignore file in the configuration directory, to ensure that the files are excluded from the repository.

I'd sort of advise against altering the config:export behavior itself, because the general assumption is that the staged configuration is a complete copy of the active one. A subsequent config:import will delete configuration objects that aren't exported. (This doesn't apply if you're exporting to a tar archive, of course.)