Add sendmail to the utuils used by the st2 linux pack

[FileMagic]

This is referenced in #60.
Closes #60

[CLAassistant]

All committers have signed the CLA.

[guzzijones]

we discovered this while testing a rule in stackstorm-k8 that sends an email using the core.send_mail action.

[guzzijones]

@armab can you give a second pair of eyes to this and merge it in please.

[arm4b]

Thanks for the contribution.
LGTM, considering we rely on it in the core st2 pack.

For the info, how much sendmail package adds to the image size?

[guzzijones]

I don't have those numbers. we do not have an internal mirror for ubuntu to rebuild this image.

[FileMagic]

To Answer The Size Question

So it looks like it is about 4MB increase.

Sorry if I am missing anything I snipped out some of my personal containers:

Current Master Branch

┌─[file_magic@parrot]─[~/external_binarys/st2-dockerfiles]
└──╼ $ docker system df -v
Images space usage:

REPOSITORY                       TAG       IMAGE ID       CREATED          SIZE      SHARED SIZE   UNIQUE SIZE   CONTAINERS
stackstorm/st2workflowengine     3.9dev    162d258cb04f   25 seconds ago   561MB     561.2MB       0B            0
stackstorm/st2web                3.9dev    59e5b21f2102   28 seconds ago   170MB     170.3MB       0B            0
stackstorm/st2timersengine       3.9dev    3a7e8e49812f   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2stream             3.9dev    788ace9b5f61   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2sensorcontainer    3.9dev    7b1f24cc2bf7   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2scheduler          3.9dev    7448ad6f024c   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2rulesengine        3.9dev    d74540784739   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2notifier           3.9dev    d165e0edb54e   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2garbagecollector   3.9dev    0116ffade96f   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2chatops            3.9dev    b02ddb8c6646   2 minutes ago    464MB     464.5MB       0B            0
stackstorm/st2auth               3.9dev    ed0fefa52254   4 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2api                3.9dev    7d7bf0612455   4 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2actionrunner       3.9dev    c67734bf1737   4 minutes ago    568MB     567.9MB       0B            0
stackstorm/st2                   3.9dev    d2248d7bd12c   5 minutes ago    561MB     561.2MB       0B            0
ubuntu                           22.04     1f6ddc1b2547   2 weeks ago      77.8MB    77.81MB       0B            0
ubuntu                           focal     88bd68917189   7 weeks ago      72.8MB    72.78MB       0B            0

The sendmail Branch

 ┌─[file_magic@parrot]─[~/external_binarys/file-magic-st2-dockerfiles]
└──╼ $docker system df -v
Images space usage:

REPOSITORY                       TAG       IMAGE ID       CREATED          SIZE      SHARED SIZE   UNIQUE SIZE   CONTAINERS
stackstorm/st2workflowengine     3.9dev    0377405b7989   7 seconds ago    561MB     561.2MB       0B            0
stackstorm/st2web                3.9dev    d77b3c966f3e   10 seconds ago   170MB     170.3MB       0B            0
stackstorm/st2timersengine       3.9dev    7ca959e65f93   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2stream             3.9dev    cef8bb9f4975   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2sensorcontainer    3.9dev    c04e171f32f7   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2scheduler          3.9dev    08014ab83b00   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2rulesengine        3.9dev    d1ca8ca2d3ef   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2notifier           3.9dev    01d4887740bb   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2garbagecollector   3.9dev    704b89a60e7f   2 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2chatops            3.9dev    dc7dcd4c20d7   2 minutes ago    464MB     464.5MB       0B            0
stackstorm/st2auth               3.9dev    34e3992f7ded   4 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2api                3.9dev    4c93900db8cf   4 minutes ago    561MB     561.2MB       0B            0
stackstorm/st2actionrunner       3.9dev    7b5242b589ee   4 minutes ago    572MB     571.8MB       0B            0
stackstorm/st2                   3.9dev    495438b939f1   6 minutes ago    561MB     561.2MB       0B            0
ubuntu                           22.04     1f6ddc1b2547   2 weeks ago      77.8MB    77.81MB       0B            0
ubuntu                           focal     88bd68917189   7 weeks ago      72.8MB    72.78MB       0B            0

[arm4b]

Thanks for sharing more info @FileMagic ! 💯