Allow authors to edit a conversation (excluding the seed opinions)

[e32wong]

Changes

• Fixed a few errors that prevents production compilation of the code
• Added the ability to edit a conversation
• Refactored the conversation components to use a new common composable for editing and creation
• The conversation table had been refactored to allow for pointing to a new poll whenever a conversation's poll had been edited, each poll response will now be mapped against a poll ID instead of being mapped against a conversation ID
• Fixed a bug where the poll ID was not recorded properly inside the conversation_content table (auto migrated with flyway)
• Added an edited indicator for conversations that had been edited