BcFamilyAlbum - the backend service

Changelog

0.3.5 2020-05-02          Add option to refresh the album cache
0.3.4 2020-04-26 6924be45 Small improvement, correctly refresh internal album structures after item removal. Lock file internaly before removing, 
                          FIX an error when you try to delete video that is being streamed at the moment
0.3.3 2020-04-22          FIX Add some semaphors to prevent race condition between picture rotation and returning it to the frontend
                          because both requires physical access to the picture file
0.3.2 2020-04-19          FIX Skip non-media files from album metadata, refactor and enhance model classes to add picture rotation
0.3.1 2020-04-15 36dd0dcb FIX workaround some problems with storing not null default-valued timestamps in SQLite
                          remove empty directories from album data returning to the frontend
0.3.0 2020-04-13 88d1cd3b FIX better CORS support, introduce DB migrations
                          store info about files deleted from the album to ignore them in future
0.2.0 2020-04-12 e60cef54 Add prototype of a persistence layer through EF Core and SQLite
                          Reorganize source code repository structure
0.1.1 2020-04-11 03e1a378 Returning pictures and streaming videos to the frontend
0.1.0 2020-04-09 07e04b97 First version that actually return album metadata, changes in data format 
0.0.2 2020-04-07 7f253fc9 Returning mocked data via dedicated provider, add CORS handling
0.0.1 2020-04-06 c0fb206a First version, returning mocked data