Re-structure sat-rs

- Add new shared subcrate satrs-shared to split off some shared
  components not expected to change very often.
- Renmame `satrs-core` to `satrs`. It is expected that sat-rs will remain
  the primary crate, so the core information is superfluous, and core also
  implies stability, which will not be the case for some time.

automation/Jenkinsfile

@@ -47,7 +47,7 @@ pipeline {
     }
     stage('Check Cross Embedded Bare Metal') {
       steps {
-        sh 'cargo check -p satrs-core --target thumbv7em-none-eabihf --no-default-features'
+        sh 'cargo check -p satrs --target thumbv7em-none-eabihf --no-default-features'
       }
     }
     stage('Check Cross Embedded Linux') {