Rework FreeBSDResourceDiskHandler

[lwhsu]

Description

Replace using a swap file in the file system of the resource disk by
using a swap partition, which is the preferred swap device. This also
avoids using the slower posix_fallocate(2) and helps increasing VM
provision speed.

Also add support for generation 2 VMs.

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PR information

• The title of the PR is clear and informative.
• There are a small number of commits, each of which has an informative message. This means that previously merged commits do not appear in the history of the PR. For information on cleaning up the commits in your pull request, see this page.
• Except for special cases involving multiple contributors, the PR is started from a fork of the main repository, not a branch.
• If applicable, the PR references the bug/issue that it fixes in the description.
• New Unit tests were added for the changes made and Travis.CI is passing.

Quality of Code and Contribution Guidelines

• I have read the contribution guidelines.

[msftclas]

All CLA requirements met.

[codecov]

Codecov Report

Merging #1892 (88ad74e) into develop (a07e48a) will decrease coverage by 1.54%.
The diff coverage is 5.83%.

❗ Current head 88ad74e differs from pull request most recent head 54de935. Consider uploading reports for the commit 54de935 to get more accurate results

@@             Coverage Diff             @@
##           develop    #1892      +/-   ##
===========================================
- Coverage    71.95%   70.40%   -1.55%     
===========================================
  Files          104       97       -7     
  Lines        15765    14053    -1712     
  Branches      2244     2026     -218     
===========================================
- Hits         11343     9894    -1449     
+ Misses        3906     3712     -194     
+ Partials       516      447      -69     

Impacted Files	Coverage Δ
azurelinuxagent/daemon/resourcedisk/freebsd.py	11.44% <5.83%> (-1.43%)	⬇️
azurelinuxagent/common/protocol/goal_state.py	91.64% <0.00%> (-3.12%)	⬇️
azurelinuxagent/ga/update.py	87.62% <0.00%> (-3.09%)	⬇️
azurelinuxagent/common/conf.py	77.25% <0.00%> (-2.59%)	⬇️
azurelinuxagent/common/cgroupstelemetry.py	98.11% <0.00%> (-1.89%)	⬇️
azurelinuxagent/common/utils/cryptutil.py	43.92% <0.00%> (-1.87%)	⬇️
azurelinuxagent/common/protocol/hostplugin.py	85.99% <0.00%> (-1.78%)	⬇️
azurelinuxagent/common/cgroupconfigurator.py	70.50% <0.00%> (-1.43%)	⬇️
azurelinuxagent/agent.py	57.43% <0.00%> (-1.20%)	⬇️
azurelinuxagent/common/protocol/wire.py	77.36% <0.00%> (-0.88%)	⬇️
... and 39 more

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[lwhsu]

@trstringer Please review and merge this. Thanks!

[svmhdvn]

I'd like to request a review of this PR if possible. We are still carrying this patch downstream (https://cgit.freebsd.org/ports/tree/sysutils/azure-agent/files/patch-azurelinuxagent_daemon_resourcedisk_freebsd.py) and would like to upstream it.