Added a method to create a new link manually JabRef#11017

- Fixed findObsoleteLocalizationKeys() error by removing unwanted keys.
- Fixed findMissingLocalizationKeys() by adding "Add file link" as a key

src/main/resources/l10n/JabRef_en.properties

@@ -530,7 +530,6 @@ Language=Language
 Last\ modified=Last modified
 LaTeX\ AUX\ file\:=LaTeX AUX file\:
 
-Link=Link
 Memory\ stick\ mode\ -\ Store\ preferences\ in\ 'jabref.xml'\ in\ the\ app\ folder.=Memory stick mode - Store preferences in 'jabref.xml' in the app folder.
 
 Show\ advanced\ hints\ (i.e.\ helpful\ tooltips,\ suggestions\ and\ explanation)=Show advanced hints (i.e. helpful tooltips, suggestions and explanation)
@@ -2508,6 +2507,7 @@ Show\ Diff=Show Diff
 Only\ show\ changed\ fields=Only show changed fields
 
 Edit\ file\ link=Edit file link
+Add\ file\ link=Add file link
 
 (Note\:\ If\ original\ entries\ lack\ keywords\ to\ qualify\ for\ the\ new\ group\ configuration,\ confirming\ here\ will\ add\ them)=(Note: If original entries lack keywords to qualify for the new group configuration, confirming here will add them)
 Assign=Assign
@@ -2638,7 +2638,6 @@ Ask\ every\ time=Ask every time
 Value\ is\ not\ in\ Unicode's\ Normalization\ Form\ "Canonical\ Composition"\ (NFC)\ format=Value is not in Unicode's Normalization Form "Canonical Composition" (NFC) format
 
 Group\ icons=Group icons
-Source\ URL=Source URL
 Redownload\ file=Redownload file
 Redownload\ missing\ files=Redownload missing files
 Redownload\ missing\ files\ for\ current\ library?=Redownload missing files for current library?