Add QC functionality to Expert Database pages

[AntonPetrov]

• [ ] RNA type pie chart (e.g. database X has 30% snoRNA, 70% lncRNA)
• [ ] pie chart with other databases that link to the same sequences (e.g. 70% link to ENA, 20% to Rfam, 10% don't have any other links)
• [ ] links and counts of entries with Rfam problems (contamination, incomplete sequences etc)
• [ ] number of sequences and cross-references over time
• [ ] create per-database reports with problematic entries and store them on FTP site
• [ ] links and counts of entries with high coding potential or overlap with Pfam/UniProt