Added nodes.read endpoint so you can query by hostname to get the system_id indirectly

[dandruczyk]

The nodes endpoint is completely missing in facade.py Added the nodes.read (thus client.nodes.read(hostnames=[]) This allows for querying maas by hostname QUICKLY which gets you the system_id which you can then query for full machine detail. This a workaround due to clien.machines.read() only accepting a system_id argument unlike the maas Client API distributed with maas since at least 2.6.2 which supports querying on a wide variety of criteria see #238

[codecov-commenter]

Codecov Report

Merging #239 into master will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #239      +/-   ##
==========================================
- Coverage   67.98%   67.98%   -0.01%     
==========================================
  Files          70       70              
  Lines        5726     5728       +2     
  Branches      988      988              
==========================================
+ Hits         3893     3894       +1     
- Misses       1610     1611       +1     
  Partials      223      223              

Impacted Files	Coverage Δ
maas/client/facade.py	93.75% <50.00%> (-1.13%)	⬇️

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[codecov-io]

Codecov Report

Merging #239 (0053170) into master (575d3f7) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

❗ Current head 0053170 differs from pull request most recent head 1896d59. Consider uploading reports for the commit 1896d59 to get more accurate results

@@            Coverage Diff             @@
##           master     #239      +/-   ##
==========================================
- Coverage   67.98%   67.98%   -0.01%     
==========================================
  Files          70       70              
  Lines        5726     5728       +2     
  Branches      988      988              
==========================================
+ Hits         3893     3894       +1     
- Misses       1610     1611       +1     
  Partials      223      223              

Impacted Files	Coverage Δ
maas/client/facade.py	93.75% <50.00%> (-1.13%)	⬇️

---

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 1f63780...1896d59. Read the comment docs.

[cpg1111]

Thanks for the contribution! Can you please add a test for this in this file https://github.com/maas/python-libmaas/blob/master/maas/client/tests/test_facade.py ?