Initial Blazar support #2048

[micafer]

Add Initial Blazar support

Description

This PR adds initial support for the blazar service (#2048), listing the available leases and hosts.

Status

Replace this: describe the PR status. Examples:

• work in progress

Checklist (tick everything that applies)

• [x] Code linting (required, can be done after the PR checks)
• [ ] Documentation
• [x] Tests
• [x] ICLA (required for bigger changes)

[codecov-commenter]

Codecov Report

:x: Patch coverage is 96.34146% with 3 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 83.40%. Comparing base (c899034) to head (e7df9ed).

Files with missing lines	Patch %	Lines
libcloud/test/compute/test_openstack.py	92.00%	0 Missing and 2 partials :warning:
libcloud/compute/drivers/openstack.py	98.21%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##            trunk    #2049      +/-   ##
==========================================
+ Coverage   83.39%   83.40%   +0.01%     
==========================================
  Files         353      353              
  Lines       81696    81777      +81     
  Branches     8634     8639       +5     
==========================================
+ Hits        68123    68201      +78     
- Misses      10750    10751       +1     
- Partials     2823     2825       +2     

Files with missing lines	Coverage Δ
libcloud/test/common/test_openstack_identity.py	97.10% <100.00%> (ø)
libcloud/compute/drivers/openstack.py	84.85% <98.21%> (+0.51%)	:arrow_up:
libcloud/test/compute/test_openstack.py	94.47% <92.00%> (-0.03%)	:arrow_down:

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