ISCE_HOME was only used to get the location of the default logging config.
Lots of scripts were using boilerplate to set up this config, so I added
an `isce.logging` helper module which is the same as builtin python logging
but already has the configuration defaults set up for isce.
ISCE_HOME setup is retained in the toplevel `__init__.py`
but can now be removed without affecting functionality.
Deployed docker image should be able to be pulled via e.g. `docker pull isce2:v2.3.2`.
Doing a `docker pull isce2:latest` still pulls the deployed docker image from the
most recent of these three circleci jobs: PR merge, weekly build, or release.
- renamed "build" job to "test" and created "test" workflow
- will run on all pull requests and merges into master
- "build" job now builds isce docker container
- "deploy" job will deploy docker image to dockerhub at isce/isce2 (https://cloud.docker.com/u/isce/repository/list)
- need to configure DOCKER_PASS and DOCKER_USER in "Build Settings" -> "Envrionment Variables" on circleci
- created "build-deploy" workflow to run "build" job then "deploy" job on merge of PR to master
- created "build-periodically" workflow to run "build-periodically" job then "deploy" job once a week