Updated Readmes; renamed servers to reference servers

Docker/reference-servers/solargraph/Dockerfile

@@ -0,0 +1,17 @@
+FROM alpine:3.22.1
+
+ARG VERSION=0.55.1
+LABEL version="${VERSION}"
+
+RUN apk add --no-cache \
+  g++=14.2.0-r6 \
+  gcc=14.2.0-r6 \
+  git=2.49.1-r0 \
+  make=4.4.1-r3 \
+  ruby=3.4.4-r0 \
+  ruby-dev=3.4.4-r0 \
+  zlib-dev=1.3.1-r2 \
+  && gem install \
+    solargraph -v ${VERSION}
+
+CMD [ "/usr/local/bundle/bin/solargraph", "stdio" ]