simpify obj input args for `tsview/plot_tran*/plot_coh*_mat*`

[yunjunz]

Description of proposed changes

Simplify the input arguments for object initiation for tsview, plot_transection and plot_coherence_matrix:

• for each *Viewer object init(): replace cmd/iargs with inps, as the later covers both, and simpler.

• for each *Viewer configure(): rename to open() for simplicity

Reminders

• [x] Fix #977
• [x] Pass Pre-commit check (green)
• [x] Pass Codacy code review (green)
• [x] Pass Circle CI test (green)
• [x] Make sure that your code follows our style. Use the other functions/files as a basis.
• [x] If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.