Fix Docker node_modules and search_meta shadowing

[ericsandu]

This commit fixes #554 which is caused by the container not having access to installed node_modules directory, there being the possibly of it getting overwritten / shadowed by a currently existing one. The instructions in README.md have been accordingly to fix this problem by forcing the use of the containers node_modules directory.

During testing I also discovered the possibility of the search-meta configuration getting overwritten, so the Dockerfile has been updated to generate it at runtime, preventing this issue.

[ericsandu]

I've updated the Dockerfile to include gcompat on top of libc6-compat to fix compilation errors with native modules (like esbuild) which occured on the current configuration, likely due to the use of an Alpine base that uses musl instead of glibc.

I've also added openssl and git, them being dependencies of used modules like octokit, husky and lint-staged which are needed for the metadata scripts and dev tools to run properly inside the container.

In regards to the linter errors I am not exactly knowledgeable on what specific version I should mention for the installed packages and if it even if a good idea to force versions directly. Advice would be greatly appreciated.

[ericsandu]

I have changed the Docker instructions in the README.md to instruct the user to use a named volume for the node_modules of the documentation, named appropriately as unikraft_modules.

Now this module will be shared between multiple docker instances of the documentation that might be running, and allow easy removal of it instead of having dangling anonymous volumes after the removal of the containers.