[mindlogger] Implementation ML integration POC1

[yagurdmitriy]

Brief summary of changes

• Implemented module for receiving ML applet schemas, sving in the Loris db and creating instruments.
• Updated base instrument class to handle ML applet instruments.
• Added base ML instrument class to handle to process ML applet schemas

Testing instructions

1. Login to the Loris API with user that have right "mindlogger_schema_create"
2. Make authorized request to Post: /mindlogger/v1/schema/ with valid applet schema.
3. Go to '$LORISURL/instrument_manager/'. You should see new ML instrument there
4. Got to '$LORISURL/dictionary/'. You should see new ML instruments fields in the fields list

[ridz1208]

@driusan I rebased it to 25 for better viewing of changes