Added routes and functions to start/stop monitoring resource usage of apps.

[johnhanlon86]

API routes and functions added to:

1. Start monitoring app/s (app name can be included as a parameter, otherwise it applies to all apps).
2. Stop monitoring app/s (app name can be included as a parameter, otherwise it applies to all apps & delete data can also be added as a parameter to delete existing in-memory monitoring data).

Docker container stats stream function also added to the docker service.

[lgtm-com[bot]]

This pull request introduces 12 alerts when merging 9214a38b46920254e0d8f63241bf3c390dc1917f into 30547a89627e618da13264ab308926f7e4a2fe98 - view on LGTM.com

new alerts:

• 6 for Assignment to constant
• 4 for Useless conditional
• 2 for Superfluous trailing arguments

[lgtm-com[bot]]

This pull request introduces 8 alerts when merging 1126acf9cbf992a55b96658791fb1491fa7d543f into 30547a89627e618da13264ab308926f7e4a2fe98 - view on LGTM.com

new alerts:

• 4 for Useless conditional
• 2 for Assignment to constant
• 2 for Superfluous trailing arguments