Add supporting themes required for Lotusdocs

themes/twbs/bootstrap/site/data/grays.yml

@@ -0,0 +1,18 @@
+- name: 100
+  hex: '#f8f9fa'
+- name: 200
+  hex: '#e9ecef'
+- name: 300
+  hex: '#dee2e6'
+- name: 400
+  hex: '#ced4da'
+- name: 500
+  hex: '#adb5bd'
+- name: 600
+  hex: '#868e96'
+- name: 700
+  hex: '#495057'
+- name: 800
+  hex: '#343a40'
+- name: 900
+  hex: '#212529'