feat: database support, expr filtering, and skip-name flag when downloading & an update flag when exporting

[powerfulsaber]

Adds multiple features:

Database support

Saves a message's channel ID and message ID to an SQLite3 database once it completes downloading. If the same message is encoutered again, it'll skip over it even if it's been moved or deleted.

Examples:
tdl dl --db PATH -u https://t.me/tdl/1
tdl dl --db PATH -f JSON

Filtering support

Similar to -f when exporting a chat, but for downloading instead. Filters based on values available in a JSON file
of an exported chat. Useful when you plan on using different filters on the same chat, but don't want to repeatedly export it every time.

Example:
tdl dl --filter FILTER -f JSON

Skip-name flag

Similar to skip-same, but skips only based on filename. It relies only on a JSON file of an exported chat, so it's significantly faster than its counterpart. If used with the database flag, it'll automatically add the skipped files to the database.

Example:
tdl dl --skip-name -f JSON

Update flag

Adds/prepends new messages to a JSON file of an exported chat. It looks for messages past the latest message in the JSON file based on its timestamp. Requires the with-content flag to be used for timestamps to be included in the JSON file.

Example:
tdl chat export --with-content --update -c CHANNEL -o JSON

Prettier JSON

Formats the JSON output with indentation for readability.

[powerfulsaber]

I plan on eventually splitting this apart to separate pull requests.