MDL-37085 Minor UI and code improvements in print_section()
MDL-37085 separated logic and html in make_editing_buttons()

- added function course_get_cm_edit_actions()
- added function core_course_renderer::course_section_cm_edit_actions()
- removed completely presently not working moveup/movedown controls
- removed not working duplicate controls from front page
MDL-37085 Substitute get_print_section_cm_text() with cm_info functions
MDL-37085 get_module_metadata() now returns link as moodle_url instead of string
MDL-37085 Load modchooser only when needed
MDL-37085 Substitute function print_section_add_menus() with core_course_renderer::course_section_add_cm_controls()
MDL-37085 Moved completion info box rendering code to renderer

Was part of function print_section(), now it is
new function core_course_renderer::course_section_cm_completion()
MDL-37085 fixed mess with code overwriting cm_info properties

In case when groupmode is forced by the course we should take it from the
course and not overwrite cm_info::groupmode externally
MDL-37085 partly moved code from print_section() to renderer

- added function core_course_renderer::course_section_cm_name()
- added function core_course_renderer::course_section_cm_text()
- added function core_course_renderer::course_section_cm_availability()
MDL-37085 Move print_section() to the course renderer

Added two functions in the renderer:
- core_course_renderer::course_section_cm_list()
- core_course_renderer::course_section_cm()
MDL-37085 Properly deprecated functions print_xxx() from course/lib.php

- get_print_section_cm_text()
- print_section_add_menus()
- print_section()
- make_editing_buttons()