Remove spacesOss plugin (#109258) (#109649)

# Conflicts:
#	.eslintrc.js
#	.github/CODEOWNERS
#	src/plugins/dashboard/kibana.json

Author: jportner

.eslintrc.js

@@ -1571,7 +1571,6 @@ module.exports = {
     {
       files: [
         'src/plugins/security_oss/**/*.{js,mjs,ts,tsx}',
-        'src/plugins/spaces_oss/**/*.{js,mjs,ts,tsx}',
         'x-pack/plugins/encrypted_saved_objects/**/*.{js,mjs,ts,tsx}',
         'x-pack/plugins/security/**/*.{js,mjs,ts,tsx}',
         'x-pack/plugins/spaces/**/*.{js,mjs,ts,tsx}',