add Dockerfile for fastkmer

.gitignore

+.DS_Store

src/fastkmer/Dockerfile

+FROM rust:1.67-alpine3.17 AS build
+
+RUN apk add --no-cache musl-dev pkgconfig openssl-dev \\
+  && cargo install --git https://github.com/angelovangel/fastkmers.git
+
+FROM alpine:3.17
+
+COPY --from=build /usr/local/cargo/bin/fastkmers /usr/bin/
+RUN apk add --no-cache procps bash