Aligned specs for oneDAL headers/namespaces with the decision taken (#170)

* Aligned specs for oneDAL headers/namespaces with the decision taken

* Added algorithm folder placement

Author: amgrigoriev

source/elements/oneDAL/source/common_interface/header_files_and_namespaces.rst

@@ -10,20 +10,21 @@ oneDAL public identifiers are represented in the following header files:
 
    * - Header file
      - Description
-   * - ``onedal/onedal.hpp``
+   * - ``oneapi/dal.hpp``
      - The main header file of oneDAL library.
-   * - ``onedal/algo/%ALGO%/%ALGO%.hpp``
+   * - ``oneapi/dal/algo/%ALGO%.hpp``
      - A header file for a particular algorithm.
+       The folder for the algorithm itself is ``oneapi/dal/algo/%ALGO%/``.
 
        The string %ALGO% should be substituted with the name of the algorithm, for example, ``kmeans`` or ``knn``.
 
-   * - ``onedal/algo/misc/%FUNC%/%FUNC%.hpp``
+   * - ``oneapi/dal/algo/misc/%FUNC%.hpp``
      - A header file for miscellaneous data types and functionality that is intended to be used by oneDAL algorithms and applications
        of the analytical pipeline.
 
        The string %FUNC% should be substituted with the functionality name, for example, ``mt19937`` or ``cross_enthropy_loss``.
 
-   * - ``onedal/util/%UTIL%.hpp```
+   * - ``oneapi/dal/util/%UTIL%.hpp```
      - A header file for auxiliary functionality, such as memory allocators or type traits, that is intended to be used for the design of classes and implementation of various methods.
 
        The string %UTIL% should be substituted with the auxiliary functionality name, for example, ``usm_allocator`` or ``type_traits``.
@@ -43,23 +44,24 @@ oneDAL functionality is represented with a system of C++ namespaces described be
 
    * - Namespace
      - oneDAL content
-   * - ``onedal``
-     - The namespace of the library that contains externally exposed data types, processing and service functionality of oneDAL.
-   * - ``onedal::%ALGORITHM%``
+   * - ``oneapi::dal``
+     - The namespace of the library that contains externally exposable data types, processing and service functionality of oneDAL.
+   * - ``oneapi::dal::%ALGORITHM%``
+
      - The namespace of the algorithm.
        All classes and structures related to that algorithm shall be defined within a particular namespace.
 
        To define a specific algorithm, the string %ALGORITHM% should be substituted with its name,
-       for example, ``onedal::kmeans`` or ``onedal::knn``.
+       for example, ``oneapi::dal::kmeans`` or ``oneapi::dal::knn``.
 
-   * - ``onedal::misc``
+   * - ``oneapi::dal::misc``
      - The namespace that contains miscellaneous data types and functionality intended to be used by oneDAL algorithms
        and applications for algorithm customization and optimization on various stages of the analytical pipeline.
    * - ``%PARENT%::detail``
      - The namespace that contains implementation details of the data types and functionality for the parent namespace.
        The namespace can be on any level in the namespace hierarchy.
 
        To define a specific namespace, the string %PARENT% should be substituted with the namespace for which the details are provided,
-       for example, ``onedal::detail`` or ``onedal::kmeans::detail``.
+       for example, ``oneapi::dal::detail`` or ``oneapi::dal::kmeans::detail``.
 
        The application shall not use any data types nor call any functionality located in the ``detail`` namespaces.