services/io/podio: remove unused datamodel_LinkDef.h

[veprbl]

Briefly, what does this PR introduce?

Removing it as it should be irrelevant for recent PODIO with frames format.
Resolves: #1693

What kind of change does this PR introduce?

• Bug fix (issue #Remove src/services/io/podio/datamodel_LinkDef.h #1693)
• New feature (issue #__)
• Documentation update
• Other: __

Please check if this PR fulfills the following:

• Tests for the changes have been added
• Documentation has been added / updated
• Changes have been communicated to collaborators

Does this PR introduce breaking changes? What changes might users need to make to their code?

Not supposed to

Does this PR change default behavior?

No

[github-actions]

Capybara summary for PR 1704

• rec_dis_10x100_minQ2=0_craterlake
• rec_dis_10x100_minQ2=1000_craterlake_tracking_only
• rec_dis_18x275_minQ2=0_craterlake_18x275
• rec_dis_18x275_minQ2=1000_craterlake_18x275
• rec_dis_5x41_minQ2=0_craterlake_5x41
• rec_e_1GeV_20GeV_craterlake
• rec_pi_1GeV_20GeV_craterlake
  ^{_{Last updated 2025-01-14T21:40-05:00 3f28345}}

[wdconinc]

Minimum JANA2 version update in CMakeLists.txt?

[veprbl]

Why?

[wdconinc]

Sorry, I meant minimum podio version?

[veprbl]

I tought the fact that we are using frames is already the threshold, but this is all guesses.

We can't set PODIO requirement low enough without implementing icky logic to support both 0.x.y and 1.x.y. (That is a cmake thing)