jdsl selectFrom function

[kihwankim]

Backgrounds

• queryDSL has selectFrom function and users migrating from QueryDSL to Kotlin-JDSL are forced to use the select() from() functions or develop an selectFrom extension function and use

Requirements

• adding the 'selectFrom' function to the 'Jdsl' class makes it easier for people to use JDSL

Example

    authorRepository.findAll {
          selectFrom(
              entity(Author::class),
              leftJoin(BookAuthor::class).on(path(Author::authorId).equal(path(BookAuthor::authorId))),
          ).where(
              path(BookAuthor::authorId).isNull(),
          ).orderBy(
              path(Author::authorId).asc(),
          )
      }