chore: Remove database ID dependency for SSH Tunnel creation

[geido]

SUMMARY

This PR removes the requirement to pass a database ID to the SSHTunnel command. It also removes the premature call of SQLAlchemy ORM listeners, such as after_insert, caused by the use of flush and begin_nested.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N.A.

TESTING INSTRUCTIONS

• Create an SSH server.
• Make sure that this server is accessible from the Preset IPs.
• Create a DB connection.
• Restrict access to the DB so that only traffic from the SSH server is accepted.
• Try setting up the connection via SSH on a Preset Workspace.
• All tests should pass

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (8a2f7d3) 67.31% compared to head (9a93efa) 69.66%.
Report is 65 commits behind head on master.

Files	Patch %	Lines
superset/commands/database/create.py	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #26989      +/-   ##
==========================================
+ Coverage   67.31%   69.66%   +2.34%     
==========================================
  Files        1895     1895              
  Lines       74202    74224      +22     
  Branches     8219     8219              
==========================================
+ Hits        49949    51705    +1756     
+ Misses      22204    20470    -1734     
  Partials     2049     2049              

Flag	Coverage Δ
hive	53.80% <23.80%> (?)
mysql	78.00% <95.23%> (+0.02%)	⬆️
postgres	78.10% <95.23%> (+0.02%)	⬆️
presto	53.75% <23.80%> (?)
python	83.06% <95.23%> (+4.85%)	⬆️
sqlite	77.62% <23.80%> (-0.04%)	⬇️
unit	56.48% <66.66%> (?)

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[eschutho]

I think this looks really good. Thanks @geido. My only question is around whether we need the add param on the db dao.

[betodealmeida]

Looks good, I just left a few comments.