Add LetMeReShade Plugin

[itsOwen]

LetMeReShade Plugin

A seamless ReShade integration for Steam Deck that enables advanced shader customization and graphics enhancement. This plugin provides easy ReShade installation, game-specific shader application, and preset management.

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.

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.
• No: 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 on SteamOS Stable or Beta update channel.

[EMERALD0874]

@itsOwen This plugin has similar issues we're addressing with #751 regarding curl statements being moved to the remote binary system. I'd rather not create standards for what should(n't) be using that system across multiple PRs, so I'm going to hold off on a code review until we're either blocked on that PR or we've agreed on a solution.