Ignore .devcontainer when checking for empty directory on project generation

[dlouwers]

Current issue

We are doing all our development inside devcontainers. This means that on bootstrapping a project there will always be a .devcontainer folder in the root of the project. This will provide, in our case, bun and node. At this point we would run bun create but that's not possible cause there is a .devcontainer folder present.

Proposed solution

create rescript-app ignores any .devcontainer folder as this is presumed to be necessary for bootstrapping.

Current workaround

After starting the devcontainer move the .devcontainer folder to /tmp and move it back after project creation.