feat: add external vcard-cli

__external/vcard-qr/README.md

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+# vcard-qr
+Generate basic VCard QR codes from your terminal. Stick them on your things so people can contact you if they get lost!
+
+This little program is only vaguely serious; I wrote it after hearing about Tile's [lost and found labels](https://www.tile.com/product/lost-and-found-labels) product, which will run you *$15* for... some QR codes pointing to a web page with your information on it. Now, I'm not exactly sure what the total cost of a mass-produced sticker sheet and a few kilobytes of database storage is, but I'm going to make an educated guess and say its somewhere in the ballpark of a few pennies. 
+
+"What a ripoff!" I thought. "And, come to think of it, can't QR codes contain VCards...?"
+
+And thus `vcard-qr` was born.
+
+## Features
+- Interactively generate VCard QR codes.
+- Free and open source.
+- Works offline forever.
+
+Or, expressed in a way my fellow Zoomers will have an easier time understanding:
+
+![pls do not take this meme seriously](https://imgur.com/ONxH1DS.png)
+
+## Usage
+Just invoke `cargo run` or `vcard-qr` and answer the interactive prompts. Most information is optional; in accordance with the VCard spec, technically only a name is required, but you probably want to specify at least an email or a phone number. If you want, you can also specify:
+
+- A website.
+- An address or addresses.
+- A custom note.
+
+Once you've been thoroughly prompted, the program will render your VCard to the disk. By default it's formatted as a 1024x1024 PNG, but this is configurable - see below.
+
+## Configuration
+There are a few arguments you can change from the default to tweak the final output:
+- `-o`/`--output-name` - the name of the output file, sans extension. Defaults to `vcard`.
+- `-f`/`--format` - the output format of the QR code, either `png` or `svg`. Defaults to `png`.
+- `-e`/`--error-correction` - how much error correction should be baked into the QR code - `low`, `medium`, `high`, or `max`. Higher EC levels will generate larger QR codes, but can increase the chance that the code will remain readable if it's damaged. Defaults to `low`.
+- `-s`/`--size` - The height and width of the output image, in pixels. Defaults to 1024.