Add export/import functionality

[udf]

/export appends data to the temporary set (implemented as a separate index):

• when replying to media if the user has it saved, copy to temporary index (/unexport to remove from export set)
• when not replying to media, add the results of the last query (that happened in the bot's chat) to the temporary index (/unexport to remove) (prompts, also has a button for inline removal where selecting an item removes it) /cancel removes everything from the export index /commit saves the export index to a file (which is sent with /import as the caption), and clears the index

/import works similarly, but has to be the caption on a file that the bot sent

• only remove commands work (/unimport)

[udf]

v2 Try to avoid commands as much as possible /export makes it so any media sent (which you have saved) is added to the export Inline button always says what selecting amln item will do When making an inline query in the bots chat, the start button will be an export button, which adds the query results to the export, and has the same effect as /export (no batch removal because that's unintuitive) /unexport removes replied to, shows button for inline removal where selecting an item removes it /cancel removes everything from the export index /commit saves the export index to a file (which is sent with /import as the caption), and clears the index

/import works similarly, but selecting from inline removes (maybe a command to switch to a "select to keep" mode) /commit copies to main index (only if you have enough space) conflicts show the media and a message with your tags, their tags with buttons to merge (if merged is within limits), use their tags, or skip