feat: add emacs directory locals to configure rust-analyzer (#109)

.dir-locals.el is the emacs equivalent of .vim directory in the project here.

This PR adds a simple configuration to map the same rust-analyzer
configuration variable as the vim version to make use of new aya
projects seamless with emacs projects that use emacs-lsp + rust analyzer.

.dir-locals.el

@@ -0,0 +1 @@
+((lsp-mode . ((lsp-rust-analyzer-linked-projects . ["Cargo.toml", "{{project-name}}-ebpf/Cargo.toml"]))))