rebased embedr (#3511)

* skeleton of embedr service, based on bskyweb

* embedr container setup

* builds on this branch

* actual routes

* fix embedr go:embed

* tweak embedr dockerfile

* progress on embedr

* fix path params

* tweaks to build process

* try to get embedr dockerfile to install embed deps

* build this branch

* updates to match sam's output HTML

* try to unbreak embedr dockerfile

* small embedr tweak

* docker hack

* get embed.js copied over to embedr

* don't x-frame-options for embed.bsky.app

* bskyembed: remove a console.log

* use html/template for golang snippet generation

* simplify embedr API fetches

* missing file

* Rm console.log fully

---------

Co-authored-by: Dan Abramov <dan.abramov@gmail.com>

bskyweb/Makefile

@@ -14,6 +14,7 @@ help: ## Print info about all commands
 .PHONY: build
 build: ## Build all executables
 	go build ./cmd/bskyweb
+	go build ./cmd/embedr
 
 .PHONY: test
 test: ## Run all tests
@@ -43,3 +44,7 @@ check: ## Compile everything, checking syntax (does not output binaries)
 .PHONY: run-dev-bskyweb
 run-dev-bskyweb: .env ## Runs 'bskyweb' for local dev
 	GOLOG_LOG_LEVEL=info go run ./cmd/bskyweb serve
+
+.PHONY: run-dev-embedr
+run-dev-embedr: .env ## Runs 'embedr' for local dev
+	GOLOG_LOG_LEVEL=info go run ./cmd/embedr serve