Add implementation for querying all snippets with languageID.
Add implementation for querying all categories with languageID.
Add implementation for querying all authors with languageID.
Add implementation for querying all projects with languageID.
Add additional helper methods for creating initial sql select statements.
Put extra work for table relation queries.
Add implementation for querying all relations.
Add helper method for sql query execution.
Merge branch 'db-init-select' into develop