Config Generator Based On Hardware Resources

## Feature Request

#### Is your feature request related to a problem? Please describe.

The default generated CKB config does not tune the options depend on the detected hardware resources. Instead the options are best suited for the recommended hardware specification: 4 CPU cores, 8G memory, and enough SSD disk space. This means CKB does not utilize all the resources when running on a more powerful machine.

#### Describe the solution you'd like

Although uses can tweak the config options, it's hard for most users to understand those options. It's also tedious to calculate and update a bunch of options. A facade can help where users provide simple hints about how many resources CKB can use and a config generator will generate the config file for the node.

The config generator have two interfaces:

- Interface for end user: which options the end user should provide, for example, number of cores, available memory, disk space, and network bandwidth.
- Interface for CKB. Which options should the generator change based on end user options?
- db-options file for rocksdb
- Memory limit for various caches in ckb.toml
- Thread pool size, which is not configurable but based on detected cores now.

Start by defining the end-user inputs for CPU cores, memory, disk space, and network bandwidth described in the issue. Then map those inputs to the db-options file, cache limits in ckb.toml, and thread pool size. Done means the generator produces a node configuration tuned to the supplied hardware resources.

Written by the indexing model from the issue text.