create sitemap.xml

[orbeckst]

• install https://github.com/jdillard/sphinx-sitemap
• see create sitemap.xml for subprojects MDAnalysis.github.io#78

[codecov-io]

Codecov Report

Merging #34 into master will decrease coverage by 0.28%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #34      +/-   ##
==========================================
- Coverage   98.85%   98.56%   -0.29%     
==========================================
  Files           8        8              
  Lines         348      348              
==========================================
- Hits          344      343       -1     
- Misses          4        5       +1

Impacted Files	Coverage Δ
pmda/rms.py	94.11% <0%> (-5.89%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f46d992...703be5b. Read the comment docs.