[RFC] A way to configure the behaviour of custom commands

[arjunmahishi]

Currently, custom commands are pretty vanilla. It's a simple bash script that gets executed as it is. #27 extends it slightly by introducing a way to use the selected text.

But this can be so much more. If there was a way to configure/program the behavior of custom commands, it would become way more powerful than it already is. For example:

• The STDOUT of the command's out can be written to the buffer
• Custom commands need not be limited to bash/shell script. It should support any scripting language the user wants to use.
• Long-running custom commands. First execution should start the process. If the process is still running, second execution onwards it should just resurface the output window that's tailing logs. (just thinking out loud :P)

This ability will make the custom commands more reusable, long-lived, etc. This plugin could potentially support importing/exporting custom commands. Kind of like Postman collections.

The configurability/programmability should be purely optional. This is important to make sure the baseline usage of this plugin is easy to adopt and use. Power usage of this plugin should not be enforced on all users.