Replace all instances of copy.png with font awesome

[agh1]

Overview

This slices off one commit from #17259 for ease of review.

This gets rid of the copy.png icon which appears at the top of columns in the batch edit screens. A new smarty function {copyIcon} takes the field name and title and produces the appropriate markup, including screen reader text.

Before

After

[civibot]

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[eileenmcnaughton]

This $Id$ should not be added. We are leaning towards skipping the whole block where it is the same as the default (in this case it isn't due to the author tag)

[jaapjansma]

• General standards
  • Explain (r-explain)
    • PASS : The goal/problem/solution have been adequately explained in the PR.
  • User impact (r-user)
    • PASS: The change would be intuitive or unnoticeable.
  • Documentation (r-doc)
    • ISSUE: The developer documentation should be updated.
    • COMMENTS: It would be nice if the functionality introduced in this PR would be documented in the developer documentation.
  • Run it (r-run)
    • PASS: We checked the update multiple contacts screen in both dmaster and the test site of this PR. We also checked whether the copying of data still worked.
• Developer standards
  • Technical impact (r-tech)
    • PASS: The change preserves compatibility with existing callers/code/downstream.
  • Code quality (r-code)
    • PASS: The functionality, purpose, and style of the code seems clear+sensible.
  • Maintainability (r-maint)
    • PASS: The change sufficiently improves test coverage, or the change is trivial enough that it does not require tests.
  • Test results (r-test)
    • PASS: The test results are all-clear.

Although we advice to update the developer documentation we don't think it is blocking this PR.
@eileenmcnaughton or @mattwire could one of you merge this PR?