feat: add admin screens, permissions and navigation

Seven admin controllers in a "Studia BM" navigation group, guarded by
jz.bm.access_courses, jz.bm.access_schedule and jz.bm.access_materials,
with Polish and English labels. Date and time fields are checked by the
models before a save and answered as 422 on the field.

models/courses/columns.yaml

@@ -0,0 +1,17 @@
+columns:
+    name:
+        label: jz.bm::lang.courses.name
+        searchable: true
+    form:
+        label: jz.bm::lang.courses.form_type
+    semester:
+        label: jz.bm::lang.courses.semester
+    lecturer:
+        label: jz.bm::lang.courses.lecturer
+        searchable: true
+    ects:
+        label: jz.bm::lang.courses.ects
+    elective_group:
+        label: jz.bm::lang.courses.elective_group
+    sort_order:
+        label: jz.bm::lang.common.sort_order

models/courses/fields.yaml

@@ -0,0 +1,58 @@
+fields:
+    name:
+        label: jz.bm::lang.courses.name
+        type: text
+        span: left
+        required: true
+    form:
+        label: jz.bm::lang.courses.form_type
+        type: dropdown
+        span: right
+        required: true
+        options:
+            wyklad: jz.bm::lang.forms.wyklad
+            cwiczenia: jz.bm::lang.forms.cwiczenia
+            konwersatorium: jz.bm::lang.forms.konwersatorium
+            seminarium: jz.bm::lang.forms.seminarium
+            inne: jz.bm::lang.forms.inne
+    semester:
+        label: jz.bm::lang.courses.semester
+        type: number
+        span: left
+        required: true
+        default: 1
+    code:
+        label: jz.bm::lang.courses.code
+        type: text
+        span: right
+    lecturer:
+        label: jz.bm::lang.courses.lecturer
+        type: text
+        span: left
+    ects:
+        label: jz.bm::lang.courses.ects
+        type: number
+        span: right
+    assessment:
+        label: jz.bm::lang.courses.assessment
+        type: text
+        span: left
+        comment: jz.bm::lang.courses.assessment_comment
+    elective_group:
+        label: jz.bm::lang.courses.elective_group
+        type: text
+        span: right
+        comment: jz.bm::lang.courses.elective_group_comment
+    sort_order:
+        label: jz.bm::lang.common.sort_order
+        type: number
+        span: left
+        default: 0
+    syllabus_url:
+        label: jz.bm::lang.courses.syllabus_url
+        type: text
+        span: right
+    description:
+        label: jz.bm::lang.common.description
+        type: textarea
+        size: large