feat: add decky-lookup

[xXJSONDeruloXx]

Decky Lookup

Decky Lookup is a convenient Quick Access menu plugin that provides one-click access to popular gaming resources and information sites for your currently running Steam game. It automatically uses the current game's name/ID to search across multiple useful websites.

Supported Sites:

• Google Search - Quick web search for current game
• PC Gaming Wiki - Technical information, fixes and tweaks
• ProtonDB - Linux/Steam Deck compatibility reports
• HowLongToBeat - Game completion time estimates
• Steam Deck HQ - Steam Deck optimization guides
• GameFAQs - Walkthroughs and guides

The plugin falls back to the homepage of each site if no game is running.

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

[xXJSONDeruloXx]

Reviewed Animation Changer PR #755 (comment)

[EMERALD0874]

@xXJSONDeruloXx LICENSE incorrectly attributes copyright to "Hypothetical Plugin Developer" instead of yourself since you're choosing to use the BSD-3 license. Please fix this and I'll move this into testing store.

[xXJSONDeruloXx]

@EMERALD0874 should be good now!