Seperate plotter and converter

[chazeon]

Now since the plugin system is almost online as in #51, we could consider move the plotter and the converter to separate packages, and they could have their own CLI command in order to be runnable on supercomputers, and also list qha as an optional dependency, to work as a plugin for QHA.

Supporting 3 styles of CLI command is trival, only ~10 lines of modification as is shown in this commit.

---

Update: Now #51 is moved to #53.

[singularitti]

Now since the plugin system is almost online as in #51, we could consider move the plotter and the converter to separate packages, and they could have their own CLI command in order to be runnable on supercomputers, ...

Agree.

and also list qha as an optional dependency, to work as a plugin for QHA.

Not sure what does this sentence mean, :)

[chazeon]

and also list qha as an optional dependency, to work as a plugin for QHA.

Not sure what does this sentence mean, :)

Some of the components, such as the plotter or the converter, should be a part of QHA, doesn't have to depend on QHA. Depending on QHA limits their use cases since QHA is not available to be installed everywhere (such as on Habanero or other places where bigfloat could not be installed or Python is not of version 3.6).

But maybe we should put more thoughts on this because some utilities is acuatlly useful for writing those plugins though not being the main part of them.