docs: Remove numbers from sections
docs: Fix design doc index
docs: Update installation and administration guide

Update installation guide and create a separate administration guide.
docs: Add archipelago v0.4 upgrade notes
Merge pull request #23 from philipgian/feature-updatedocs

Update docs
archipelago: Add info when retrying to get a lock
filed: Rename migrate option to pithos_migrate
docs: Minor typo fix regarding pithos_upgrade
Rename RST files for admin and installation guides
Rename RST files for admin, install and upgrade guides
docs: Update installation guide
docs: Explain Archipelago mapfile architecture
Merge pull request #24 from philipgian/feature-minorfixes

Feature minorfixes
Merge pull request #25 from Erethon/develop

Documentation updates
mt-sosd: Add cephx id in options list