creates a separate package for the strings plugin (#1171)

* creates a separate package for the strings plugin

this PR removes strings plugin from `beagle` package and introduce a new
package `bap-beagle-strings` for it

* restores string plugin

* fixes typo

Author: gitoleg

oasis/beagle

@@ -20,12 +20,3 @@ Library beagle_prey
   Modules: Beagle_prey
   BuildDepends: bap, bap-primus, core_kernel, ppx_jane, monads, regular
   XMETADescription: beagle attributes
-
-Library strings_plugin
-  Build$:       flag(everything) || flag(beagle)
-  Path:         plugins/strings
-  FindlibName:  bap-plugin-strings
-  BuildDepends: bap, bap-strings, bap-beagle-prey, core_kernel, regular
-  InternalModules: Strings_main
-  XMETAExtraLines:  tags="pass, strings"
-  XMETADescription: find strings of characters

oasis/strings

@@ -1,15 +1,12 @@
 Flag strings
-  Description: Build string analysis library
+  Description: Build strings plugin
   Default: false
 
-
-Library bap_strings
+Library strings_plugin
   Build$:       flag(everything) || flag(strings)
-  Path:         lib/bap_strings
-  FindlibName:  bap-strings
-  BuildDepends: core_kernel,ppx_jane
-  Modules:      Bap_strings,
-                Bap_strings_detector,
-                Bap_strings_index,
-                Bap_strings_unscrambler,
-                Bap_strings_scanner
+  Path:         plugins/strings
+  FindlibName:  bap-plugin-strings
+  BuildDepends: bap, bap-strings, bap-beagle-prey, core_kernel, regular
+  InternalModules: Strings_main
+  XMETAExtraLines:  tags="pass, strings"
+  XMETADescription: find strings of characters

oasis/strings_library

@@ -0,0 +1,15 @@
+Flag strings_library
+  Description: Build string analysis library
+  Default: false
+
+
+Library bap_strings
+  Build$:       flag(everything) || flag(strings_library)
+  Path:         lib/bap_strings
+  FindlibName:  bap-strings
+  BuildDepends: core_kernel,ppx_jane
+  Modules:      Bap_strings,
+                Bap_strings_detector,
+                Bap_strings_index,
+                Bap_strings_unscrambler,
+                Bap_strings_scanner