Use URI.join to assemble the URL to fetch a single post

That normalizes any extra / on the base URL.
use URI.join in the specs too
BUG: new messages to person that is not sharing

Conversation recipient validated

- Conversation foreign recipient not required to be validated.
- Added 'peter' as spec_helper user.
- New fixture, new statistic values.

- Clearer identifier names
Merge pull request #5449 from margori/3016_block_messages_to_not_sharing_user

BUG: new messages to person that is not sharing
Disable spring while generating secret token

That causes a cyclic dependency on spring being
loaded otherwise.
Fix order of poll answers
Merge pull request #5471 from svbergerem/fix-poll-answer-order

Fix order of poll answers
fix some typos in the changelog [ci skip]
Bump open_graph_reader
Improve wording for tagged people on tag page
Add JSON exporter for user profile download
Destroy conversation when all participants leave it
Merge pull request #5478 from margori/Purge_orphan_conversation

Destroy conversation when all participants leave it
Merge pull request #5354 from gdpelican/feature/json-exporter

Feature/json exporter
Merge pull request #5475 from svbergerem/tag-page-improve-wording

Improve wording for tagged people on tag page
Personnalize home page, registration page and terms page
Add my aspects link in the header
Modify home page to redirect users to framasphere