RFR: 2167: Unify search methods in IssueProject [v3]

[Erik Duveblad]

> Hi all,
> 
> this patch unifies the various ways of searching that exist within `JiraProejct`. I also chose to expose the `search` method in the `IssueProject` since I will make use of it in later patches. This is the first patch of _many_ that will extract the JBS specific parts from `JiraProject` so that `JiraProject` will be about JIRA and JBS specific functionality will be moved elsewhere. This refactoring is needed to allow other parts of the Skara to use JBS functionality with only an `IssueProject` instance (without turning `JiraProject` into effectively `JbsProject`).
> 
> Thanks,
> Erik

Erik Duveblad has updated the pull request incrementally with one additional commit since the last revision:

  Fix limit

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Changes:
  - all: https://git.openjdk.org/skara/pull/1610/files
  - new: https://git.openjdk.org/skara/pull/1610/files/ef17ef1f..6abc5a55

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1610&range=02
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1610&range=01-02

  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/skara/pull/1610.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1610/head:pull/1610

PR: https://git.openjdk.org/skara/pull/1610