Plugins are installed into `scripts/plugins` which could lead to a conflict

[mickmcgrath13]

Describe the bug
Plugins are installed in scripts/plugins along side the code that runs plugins (here: https://github.com/bitovi/bitops/blob/main/scripts/plugins/settings.py#L104).
This could lead to a conflict if BitOps core defined, for example, a directory called scripts/plugins/test and someone built a plugin called test. In this example, the install process would install the plugin test to scripts/plugins/test - which would either override the core code or would error.

A better approach would be to have a dedicated directory (like scripts/installed_plugins or scripts/plugins/installed or similar). This way, any plugin would be installed into a directory that is dedicated to installed plugins (i.e. each plugin installed would only be at risk for colliding with each other rather than with the BitOps core code), and the core code could define any directory without concern of conflict from installed plugins

Expected behavior
Directories can be defined in BitOps core's scripts/plugins without concern for conflict of any named plugins.

[PhillypHenning]

Updated install_plugin.py to use the BITOPS_installed_plugins_dir variable.

Output
The important bit here being /opt/bitops/scripts/installed_plugins/aws/plugin.config.yaml now using installed_plugins

#8 1.059 ~#~#~#~INSTALLING PLUGIN [aws]~#~#~#~           
#8 1.059         PLUGIN_INSTALL_SCRIPT:             [install.sh]                  
#8 1.059         PLUGIN_INSTALL_LANGUAGE:           [bash]                
#8 1.059         PLUGIN_DEPENDENCIES:               [None]                
#8 1.059         PLUGIN_CONFIG_PATH:                [/opt/bitops/scripts/installed_plugins/aws/plugin.config.yaml]                
#8 1.059 #~#~#~#~#~#~#~#~#~#~#~#~#~#~#~#~#~#~#~#