C API integration layer

See merge request !96

gRPC and vereign services code generation

See merge request !94

[18] grpc server and Rest API http client architecture

See merge request !92

Devops change builder

See merge request !93

ability to attach visual signature on pdf document

Closes dashboard#697

See merge request !90

Add hexStringToUtf8ByteArray

See merge request !91

Revert "Added checking the case when txtBody and htmlBody is passed but they are empty (User left blank email. Roundcube version)"

This reverts commit 6b44ea63.

Added checking the case when txtBody and htmlBody is passed but they are empty (User left blank email. Roundcube version)

This reverts commit 022fec62.

This reverts commit 72df38f5.