meta: fix rust-analyzer support for aya-bpf

Ironically, we have the same issue here as in https://github.com/aya-rs/aya-template/pull/13/.
This patch fixes this by explicitly defining the project layout for both vscode and neovim.

.gitignore

@@ -1,4 +1,3 @@
 Cargo.lock
 target/
-.vscode
-libbpf/
+libbpf/

.vim/coc-settings.json

@@ -0,0 +1,3 @@
+{
+  "rust-analyzer.linkedProjects": ["Cargo.toml", "bpf/Cargo.toml"]
+}

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "rust-analyzer.linkedProjects": ["Cargo.toml", "bpf/Cargo.toml"]
+}