Web app changes; credentials insertion and schema selection JSP pages added.

.../java/it/inaf/oats/ia2/tap/tsm/datalayer/TapSchemaDL.java

...ava/it/inaf/oats/ia2/tap/tsm/datalayer/UpdateManager.java

new/src/main/java/it/inaf/oats/ia2/tap/tsm/model/Column.java

...main/java/it/inaf/oats/ia2/tap/tsm/model/Credentials.java

...rc/main/java/it/inaf/oats/ia2/tap/tsm/model/DbEntity.java

.../it/inaf/oats/ia2/tap/tsm/model/IDbEntitiesContainer.java

new/src/main/java/it/inaf/oats/ia2/tap/tsm/model/Schema.java

new/src/main/java/it/inaf/oats/ia2/tap/tsm/model/Table.java

...c/main/java/it/inaf/oats/ia2/tap/tsm/model/TapSchema.java

.../it/inaf/oats/ia2/tap/tsm/pageutil/InsertCredentials.java

...va/it/inaf/oats/ia2/tap/tsm/pageutil/SelectTapSchema.java

...rc/main/java/it/inaf/oats/ia2/tap/tsm/rest/PageModel.java

...java/it/inaf/oats/ia2/tap/tsm/rest/TapSchemaResource.java

new/src/main/webapp/WEB-INF/tags/basepage.tag

new/src/main/webapp/WEB-INF/tags/editcheckbox.tag

new/src/main/webapp/WEB-INF/tags/edittext.tag

new/src/main/webapp/css/style.css

new/src/main/webapp/editTapSchema.jsp

new/src/main/webapp/index.jsp

new/src/main/webapp/js/edit-tapschema.js