Merged in feature/track-filesize (pull request #200)

track file sizes for all documents in system

* feature complete

needs dev testing

internal/database/migrations/00000000000118_add_document_file_size.down.sql

@@ -0,0 +1,2 @@
+-- Remove file_size_bytes column from documents table
+ALTER TABLE documents DROP COLUMN file_size_bytes;

internal/database/migrations/00000000000118_add_document_file_size.up.sql

@@ -0,0 +1,4 @@
+-- Add file_size_bytes column to documents table
+-- Stores the size of the document in bytes as measured from S3 HeadObject
+-- NULL for legacy documents (before this feature was added)
+ALTER TABLE documents ADD COLUMN file_size_bytes BIGINT;