add bash-completion and motd handling (#2)

#### 📖 Summary

- adds bash completion for `install-revruntime` helper
- adds motd handling.

#### 📑 Test Plan

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- [x] Tested via Drone.io pipeline
- [ ] Custom test
- [ ] No test plan

##### Details / Justification

<!-- Add your test details or justification for missing tests here. -->

#### 📚 Additional Notes

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Co-authored-by: OCram85 <marco.blessing@googlemail.com>
Reviewed-on: CodeServer/Container#2

Dockerfile

@@ -15,6 +15,10 @@ RUN \
   echo 'source /usr/share/bash-completion/completions/git' >> /etc/bash.bashrc
 
 ADD install-devruntime /usr/bin/
+ADD install-devruntime-completion /etc/bash_completion.d/
 RUN \
   chmod +x /usr/bin/install-devruntime && \
-  echo "echo \"Use 'install-devruntime' to install missing runtimes like dotnet or NodeJs.\"" >> /etc/bash.bashrc
+  chmod +x /etc/bash_completion.d/install-devruntime-completion && \
+  echo 'source /etc/bash_completion.d/install-devruntime-completion' >> /etc/bash.bashrc && \
+  touch "$HOME/enable_motd" && \
+  echo "if [[ -e \"$HOME/enable_motd\" ]]; then echo -e \"Use \\e[32m'install-devruntime'\\e[0m to install missing runtimes like dotnet or NodeJs.\"; fi" >> /etc/bash.bashrc

install-devruntime

@@ -14,11 +14,19 @@ function showHelp() {
     nodejs        Installs latest NodeJs LTS version.
     powershell    Installs latest PowerShell LTS version.
   -h              Prints this help messagee.
+  disablemotd     Disables hint in new bash terminal
   Example 1: install-devruntime dotnet
   Example 2: install devruntime golang nodejs
 HELP
 }
 
+function disableMotd() {
+  if [[ -e "$HOME/enable_motd" ]]; then
+    say "Disabling 'install-devruntime' motd..." "disableMotd"
+    rm -f "$HOME/enable_motd"
+  fi
+}
+
 function say() {
   if [[ -n "$2" ]]; then
     echo -e "\e[32mInstall-DevRuntime\e[0m \e[34m[$2]\e[0m: $1"
@@ -122,6 +130,9 @@ function main() {
       instNodeJs
     elif [[ "$i" == "powershell" ]]; then
       instPwsh
+    elif [[ "$i" == "disablemotd" ]]; then
+      disableMotd
+      exit 0
     else
       sayE "Unknown parameter value given!($i)."
       showHelp

install-devruntime-completion

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+complete -W "disablemotd dotnet golang nodejs powershell -h" install-devruntime