/usr/sbin/iiab installer: introduce --reinstall (or --update ?) and install progress flags

[jvonau]

No description provided.

[holta]

Just called @jvonau for a cursory review of our options here — here are quick notes as to what we talked about so that thoughts are not lost:

1. I'm wondering if we should consider a flag like --update to make clear that online updates will be requested/applied going forward — above and beyond reinstalling the original code.

   (For me, the addition of git pull is overloading and overstretching the definition of --reinstall beyond the limit of what that word means, e.g. both the actual dictionary definition and popular usage of the term.)

   Something to think about. Whereas a flag like --upgrade would be overstating the case. And overkill for now — as those who really want the very latest do now have a (partially supported) upgrade path, automatically switching to the master branch of both of IIAB's main repos, as documented here:

   "Can I upgrade IIAB software?"
   http://FAQ.IIAB.IO Item 27

2. I originally placed en.zip in /tmp instead of /opt/iiab/downloads on purpose, so it would deleted itself during the next boot, freeing up 0.9 GB.

   This can be changed to /opt/iiab/downloads if truly necessary...but let's think about the pros/cons...and who/what is responsible for cleaning up /opt/iiab/downloads during implementation.

3. Small bug: Line 201 will fail if it's trying to "cd iiab-admin-console" from /opt/iiab/iiab

4. Small typos & readability things to nail in due course...

   • /opt/iiab/iiab/downloads/en.zip should be /opt/iiab/downloads/en.zip within the comments
   • friendly output (incl newlines, pagination) needed as part of the interactive script
   • internal spacing of code for readability