Add command cwd to working directory

[leakec]

Problem

I want to be able to run commands from a specific directory rather than the zellij /host directory. However, as we will see, the solution creates some other problems, namely:

• With the current setup, we can have multiple instances of the multitask plugin all pointing to the same file. When this file is changed, then all the plugin instances will run those commands from their specific cwd. This is undesirable.
• Need to use launch-or-focus-plugin to reload the config each time. start-or-launch-plugin seems to always use the starting config.

Solution

• [x] This can be done by adding a cwd option to the configuration and running command using that cwd.
• [x] Change start-or-launch-plugin to launch-or-focus-plugin in the README.
• [x] Need to use something other than /host/.multitask as the multitask file, since each plugin instance needs its own .multitask file.

[leakec]

We want to use something other than /host/.multitask. My first thought was something in /tmp, since this would also keep from cluttering up the /host folder. However, FileSystemUpdate, which is used to determine when the file is changed, only has access to the /host folder. Therefore, I think the best thing to do is create a unique .multitask file in the /host folder for each instance of the multitask plugin (there will be a unique instance for each one spawned with a different config). Luckily, we already have a unique identifier, which is the plugin ID. Therefore, I'll just append that to the name of the file, e.g., /host/.multitask1.