feat: Exhibitor: Add Contact Info column

[MeghalBisht]

For: fossasia/open-event-frontend#6649 Point 3

Short description of what this resolves:

added column contact

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

[codecov]

Codecov Report

Merging #7736 (749a20d) into development (28c8270) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           development    #7736   +/-   ##
============================================
  Coverage        67.66%   67.66%           
============================================
  Files              285      285           
  Lines            14320    14322    +2     
============================================
+ Hits              9689     9691    +2     
  Misses            4631     4631           

Impacted Files	Coverage Δ
app/api/schema/exhibitors.py	100.00% <100.00%> (ø)
app/models/exhibitor.py	89.28% <100.00%> (+0.39%)	⬆️

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