Add DeckDrop to Plugin Store

Since I develop for SteamDeck, I need fast iteration times when providing other devs with screenshots and recordings.

As the build-in tools for uploading and saving recorded media do not work for me / throw errors, and the Steam OS Devkit Client only can do screenshots and only sometimes, I decided to make a script which uses (pre-installed) ffmpeg to encode a recording and move it somewhere in my network with scp. Since finding and selecting the right folder with a new recording is tedious and slow, I decided to make this a decky plugin.

With this plugin you can copy screenshots or transcode and move recordings (and even cuts of those) via rclone to a remote provider of your choice (Samba, Nextcloud/webDAV, OneDrive/Google/Dropbox).
You have a few options for the transcode (codec/quality/audio yes/no) and the target filename is templated as <optional_suffix>_.mp4/jpg. If you feel like it, you can just select the media and click on 'GO' to copy it over.
There is a progress bar for transcode.
There are thumbnails for media selection.
Simple error reporting in the app.
The only part that requires Desktop mode is the inital creation of commercial remotes for rclone - as stated in the README. Nextcloud and Samba can be setup in gamemode.
The rclone binary is included in the release.

Task Checklist

Developer

• I am the original author or an authorized maintainer of this plugin.
• I have abided by the licenses of the libraries I am utilizing, including attaching license notices where appropriate.
• Generative AI was NOT used to write a majority of the code I am submitting.

Plugin

• I have verified that my plugin works properly on the Stable and Beta update channels of SteamOS.
• I have verified my plugin is unique or provides more/alternative functionality to a plugin already on the store.

Backend

• No: I am using a custom backend other than Python.
• No: I am using a tool or software from a 3rd party FOSS project that does not have it's dependencies statically linked.
• Yes: I am using a custom binary that has all of it's dependencies statically linked.

Community

• I have tested and left feedback on two other pull requests for new or updating plugins.
• I have commented links to my testing report in this PR.

Testing

• Tested by a third party on SteamOS Stable or Beta update channel.