Configuration file propsoal

[tigercosmos]

This proposal suggests having a configuration file for turning on/off features in Modmesh.
Currently, we may use Python script to set up some configs during runtime, such as setting modmesh.view.app.pycon.python_redirect = False, but it's inconvenient to do it again and again when we are doing some testing.

The steps should be:

1. have a new file config.{format} in json or ymal format.
2. have an in-memory config object class Config
3. when Modmesh starts, it loads the config file to Config and Modmesh initializes everything according to Config
4. when Python scripts modify config later during runtime, just change Config

There should be no overhead for Modmesh with this proposed change. This change may also benefit the later web server feature since we can expect some configurations may be required.

[tigercosmos]

cc @yungyuc, what do you think?

[yungyuc]

Thanks @tigercosmos . Remarks:

1. The configuration data processing engine should be implemented in C++. Configuration data can become very large and it is likely to require a C++ implementation. The initial proof-of-concept may use Python.
2. There needs to be comprehensive Python API wrapped for the config object.
3. The configuration objects needs serialization and deserialization. It would be good to be able to partially serialized (and deserialized).
4. For testing and further prototyping, the Python API should be made to construct the config object from scratch and manage each piece in it.