* refator(config_handler): handle and validate the updates to raw_configs
* fix(hocon): update hocon to 0.8.0
* refactor(config_handler): check and apply envs only in top-level handler
* refactor(config_handler): update config from top level to bottom level
* refactor(emqx_data_bridge): move configs to emqx.conf
* fix(emqx_schema): remove the extra config path
* fix(config_handler): load the emqx.conf when starting emqx_config_handler
* fix(data_bridge): API not working
* feat(config_handler): save updated configs to emqx_override.conf
* fix(config_handler): cannot find the emqx.conf and emqx_override.conf
* fix(emqx_config): cannot find the correct path for etc dir
* fix(test): load load emqx_schema foreign refereced apps
* refactor(emqx_plugin): do not generate configs before load plugins
All configs (including the configs for plugins) now should go into
the `emqx.conf`.
* fix(tests): update the test cases for plugins
* fix(tests): don't include schema from apps when testing
* fix(tests): use emqx-ct-helper branch hocon
emqx_moduels for enterprise is refactored as a lib/plugin
in order to avoid merge conflicts, we make sure they can
co-exist in the same branch, because lib-opensource is compiled
in opensource project and lib-enterprise (to be added) is
compiled in enterprise project
And move emqx app back to root level
After realising the challenges of developing plugins in standalone
rebar projects. it is perhaps more smooth to keep using emqx as
a rebar dependency
Starting from 5.0.0, all apps in apps dir should follow semver
strictly. Do not use the umbrella project's release tags.
The universal tags made sense when we have applications scattered
in different repos. Now since this is an umbrella project, it is
enough to have a single package level version number corelated with
git tag.
